F/S Vintage Righthand Herretts Checkered Thumb Rest Target Grips for Smith & Wesson K frame revolvers with square butt , there are three pictures below.
Asking $50 plus shipping and insurance.

http://i1106.photobucket.com/albums/h366/rojo2011/98holsytersgrips006.jpg
http://i1106.photobucket.com/albums/h366/rojo2011/98holsytersgrips002.jpg
http://i1106.photobucket.com/albums/h366/rojo2011/98holsytersgrips003.jpg