Welcome to the Forum. There is no model number for this revolver, so it is simply called a 38 Double Action revolver, only offered in 38 S&W caliber. With the re-curved trigger guard, single line of cylinder stop notches, and 177,XXX serial number, it would be a Third Model. It would have shipped around 1888.

I forgot your question about value, with a half-million 38 DAs made, only those in pristine condition would be valuable. That one looks to have lost quite a bit of its original nickel finish, so just under $200 would be my guess.

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Gary
SWCA 2515