Those are Smith and Wesson factory square butt combat grips
They were offered as an accessory for a decade or more and could be put on any square butt revolver.
One size was manufactured for K and L frames and a second size for the N-frame
Depending on frame size, wood type and condition square butt combat grips can go for $150-$300
Yours appear to be made from Goncalco Alves wood while the ones shown in the package are Morado wood