I agree with flagman1776 on your Model 657 3-inch.
The very first of the N-frame 3" round-butt Combats was the Model 24-3, followed by the 29-3, and the 624, 629, and 657 (not necessarily in that order, hey I'm getting old!). All of these had a red ramp front sight, white outline rear sight, semi-target hammer, smooth .312" trigger, and factory fingergroove Combat Stocks made of Goncalo Alves with S&W medallions.
I can't remember if all of these special orders were Lew Horton exclusives, but the exact same revolvers were also available from other distributors during their runs. These limited edition revolvers were special orders and therefore not "catalogued." This would explain the omitted 3" barrel length mention in the SCSW4th description of the Model 657.
Excellent acquisition on your part. Worth at least $1200, in my opinion, but probably more, maybe a lot more!