jamesmhebert:
Dash numbers usually refer to engineering changes. They can also refer to different calibers, barrel lengths or barrel contours.
So the 627-1 had a new rear sight leaf and the top strap was drilled and taped for a scope mount.
The 627-2 was a new frame design with the frame mounted firing pin and an 8 shot cylinder.
The 627-3 had a new frame design and metal injection molded hammer and trigger.
The 627-4 introduced the internal lock and .38 Super caliber.
the 627-5 introduced the internal lock in .357 magnum caliber.
Interestingly, the first offering of the 627-5 did come with a five inch barrel from the S&W Performance Center, at a premium price.
Now as to your gun, the serial number ranges in the Standard Catalog of S&W, which is the reference used for this thread, cut off in 2004. The 627 Pro series was announced by S&W at the 2008 SHOT show, so all I can tell you is your gun was made in the last two years.
If you are interested in the Pro series, try a search on member Stainz. He is very pleased with his, posts a pic of it regularly, and his posts will probably help you.
FWIW, the 6 in 627 refers to a stainless steel model 27. The Model 27 was for many years S&Ws flagship gun, given the best finish. It in turn was an evolution of the .357 Registered Magnum, introduced in the 1930s, the original gun for the .357 magnum. Built on S&Ws large .44 sized N frame, with a six shot cylinder, there was plenty of metal in the cylinder to withstand pressures nearly double those of the earlier blackpowder based .44 special the N frame was originally chambered in. One problem with the earlier six shot .357/.38 guns built on the N frame was that rapid double action fire could causing peening of the cylinder notches, the cylinder had too much mass. By going to an 8 shot cylinder the mass was reduced, reducing the risk of peening. Also having 8 shots made the gun more sellable in a market that thinks more is better.
Modern 627s aren't hand fitted and manufactured to order, but you don't pay the premium that the old guns pulled, not do you have to wait a couple of months for it to be made.
TL,DR: You have a fine firearm, go and shoot it.