Welcome. It has a shorter ejector shroud, so has to be a 3rd Model as stated above. It is a commercial model, not Russian contract gun and around 13,000 were made.

As for your comments, glad you followed the protocol, giving us lots of information to work with plus pictures! See notes below:

2. Possibly was Nickel Plated - Since it is a commercial gun, it is a remote possibility, but likely it was plated post-factory as well.

4. Serial Number XX on butt of gun, rear of cylinder and under latch - That would put it at 1874 manufacture year for sure.

5. .44 Special is 0.20” too long - No, 44 Russian caliber

6. Barrel length 5” (has been cut) - There is a chance that it was ordered with a short barrel, but a long-shot.

9. No Strain Screw Present - That needs a picture. All S&W Model 3 revolvers had a mainspring strain screw??

10. No Butt Swivel Present, appears to have had one - Need another picture. It was a standard feature on all commercial and Russian contract guns alike.

__________________
Gary
SWCA 2515