629-3 8 3/8 with wrong cylinder? Not enhanced?

[RogerA]

So I've been looking for a 629-3 or 629-4 in an 8 3/8 for awhile now. So tonight a 629-3 appears on a popular auction site. Nice gun with box and papers. I'm excited, but the cylinder has the short timing slots of the no dash and -1 and -2? I thought all the -3 and -4 had the enhancements that included the longer slots on the cylinder? I looked at it again, but it just looks wrong to me. What do you guys think? Thanks! Roger
PS- This is not my gun and I'm not associated with the seller.

 

[k22fan]

My guess is someone swapped cylinders in order to get the endurance package's tight throats in their preferred square butt and probably shorter barrel earlier 629. If I had reason to believe a S&W revolver no longer had its original cylinder then I would not but it without an in hand examination of carry up, lock up, end shake and BC gap. Additionally it should be checked for barrel to chamber alignment with a range rod. Cylinders are not drop in parts. Even if all that is O.K. why let someone stick you with the large throats?

 

[RogerA]

The seller answered my questions, by saying he is not the original purchaser and he has no information on the cylinder. I guess my search continues.