[Snap Cap]

Bill, I believe they are most common on the AHE grade. Also it was a common pattern on the bottom of the A1S grade reproduction guns. If you peruse the pages of the following links, I think you will find some examples.

http://parkerguns.org/forums/showthr...highlight=dogs

and

http://parkerguns.org/forums/showthr...t=14853&page=2

HTH.