Edited to ask why you're looking to replace the extractor & spring? Problem?
If so, I'd call the factory and ask to speak with a technician regarding replacement if I were in your place.
They have the extractors available in their Parts Catalog, BTW. It's available online in either .pdf or Excel format ...
http://www.smith-wesson.com/webapp/...catalogId=10001&content=13016§ionId=10504
BTW, the numerical listing for the parts runs roughly according to model, but not exactly according to numerical sequence, so look at the whole list.
The part number for a 469 extractor in the current parts catalog is #101250000 ($20.06), which is the same part number for the blued (slide) 6904 extractor, but is different than that used in the blued finish 59, 459 & 559.
Interestingly enough, the 10125 extractor is also listed as a revised (R1) extractor for the M5904, with the #10124 extractor being the original production extractor. This would commonly be taken to mean that it's a revised part which might be needed for repair purpose.
S&W has a number of extractors ... and extractor springs ... used across their different pistol model line. The difference in some part numbers may be because of something as simple as the finish/material (carbon or stainless) of the part (so it matches the given model's finish), but it might also be because of an engineering revision (such as a dimension change in the extractor hook).
Yes, S&W extractors require fitting, and this requires the use of a bar block Go/No-Go gauge to check the dimension from the end of the extractor hook to the opposite side of the breech face when the extractor is at complete rest without a case rim under it, as well as a force dial gauge to check the extractor spring tension to make sure it falls within the recommended range.
In earlier days there was another gauge used, a flag gauge, which checked the dimension between the inside (underneath) of the extractor hook and the breech face directly under it, but that gauge is no longer considered necessary, apparently because of improved production methods/tolerances and extractor design.
There's some variance permitted when using extractor springs, too. This can allow an armorer to adjust an extractor's tension to provide for optimal feeding & extraction depending on unexpected variations which may occasionally be encountered with the combination of shooter/gun/ammunition.
The factory could replace & fit an extractor for you, or you could find a licensed gunsmith who's familiar with S&W pistols and has the required gauges to check for the required tolerances.
It's not that it's a hard part to replace. Fitting requires removal of metal from the raised adjustment pad located on the inside of the extractor, which indexes against the recessed extractor slot machined into the slide. It's just that the file strokes should be in the right spot and level ... and sometimes just one too many file strokes can require fitting another extractor.
Also, I've seen the occasional slide mangled by someone who doesn't know how to use a starter punch to start the extractor pin moving downward for removal, but then a very small pin punch to complete removal. (Sometimes a spare 'starter' pin punch can be 'made' when the unexpected tension of the extractor spring causes the 1/16" pin punch shank to be bent and broken off at the base.) The pins are set with presses during production, and removing them in the field (away from the factory) requires some knowledge, experience and the right tools (including a 4 oz ball peen hammer) to remove. Replacing the pin is done from the bottom, and also requires some finesse to make sure the pin is properly seated and no burrs are raised which might drag along the top of an alloy frame once the pistol is reassembled.
Finally, using the required gauges for the recommended bench checks is fine, but the real test takes place on the firing line to make sure of proper functioning. Too much tension and you can get feeding problems. Too little tension and you can get failures to extract.
For example, when replacing extractors in early production 5903's there were two different repair extractor spring revisions available, one of which used a pair of nested springs, and the other a choice of two different weight springs other than the original. We were told the early production and machining methods resulted in some less precise tolerances than modern production equipment & methods, and some wiggle room might be needed when repairing them. Understandable. Some of the early extractor spring holes might've been machined a bit too deep or too shallow before production was done with CNC equipment.
FWIW, there was also a change in the breech face in the 9mm pistols which resulted in the rounded shoulders being eliminated, replaced with a straight cut breech face ... (with the corresponding change from a narrow barrel tab to the wide tab) ... and which resulted in a change in the recommended tolerance range of extractor spring tension.
It's not a 'drop in' or kitchen table gunsmithing repair project.
As with many other things, once you know how to do it, and have the right tools, it's not difficult most of the time.
Look at the difficulties folks encounter even when trying adjust their extractor tension on the 1911 internal extractor, though.
Just my thoughts.
If you were located close to me I'd offer to fit & install the extractor for you as a courtesy.
Best regards.
