Does a factory mis-marked model add value?

No added value...

For the most part, value is subjective as far as I'm concerned. If someone wanted to buy my first rifle, a CZ lux 452, I'd tell them $2,000. To me, it isn't worth parting with for any less.

no value

Just be careful you don't have a 29-2 with some spare parts added later in life. A friend of mine bought an M-27? (20 years ago - memory has faded) from a dealer and something didn't seem right to me, the gun was TIGHT on lockup. Turned out the dealer had swapped the cylinder from some other model (I don't know why...). He got his money back.

mutt,

No, it is not uncommon.

Mike

I don't believe it adds value. I once had a mod 28 chambered in 44 mag. It was built back when the mod 29s were in short supply. Folks bought 28s and sent them to the factory to be built into 29s. My guess (and IMHO) it wasn't improperly stamped it was sent back and caliber was changed.

No. Recessed cylinder chambers, pinned barrel and things like "NYHP, FBI, LA SWAT,....." stamped below cylinder on the frame would add some value to something like that. It should be w/o saying that stamping would have to signify belonging to such organization not someones basement or garage job.

Add value in the manner of that old postage stamp with the upside down airplane? No.

I have had opportunities to purchase mis-maked Colt Diamondbacks over the years at Gunshows. In every case, the dealer wanted a fairly substantial premium over current value. I like Diamondbacks and I considered even the elevated price, but in the end, I didn't see any substantial increase in value like you might see with a coin.

Only the hardest core collector would see any substantial increase in value over a normal M28-2 in my opinion. Those people exist, but are not abundant, hence the market for resale is very restricted at a premium price.