It appears that the tooling of the frame is that of a .38 special ; the shorter cylinder is compensated for by an extended forcing cone.
I don't see patent marks on the stocks.The ser# is stamped in the right stock.
This one has "38 S&W Ctg" on the right side of the barrel, and "SMITH & WESSON" on the left.
That is not a gun one sees every day. How did you come by it , if it's ok to ask?