Only time I used a coin on a gun was to cut out the beaver on the back of a Canadian nickel for a cheakpiece inlay. It has high relief, so itl looked pretty nice.Only a Canadian would gave known where it came from.
I used a genuine, imitation, almost real gold coin in my Hawkin rifle stock.
It is called a Racketeer coin. Faked in the 1880 years. I got the idea from Royal Tiger Imports selling of a Italian rifle from Ethiopia. It proved ownership of the rifle by the Emperor of Ethiopia. I got another Italian WWII rifle from RTI with 2 big dings in it. I decided to fill the dents with 2 Ethiopian coins I got off of eBay. I will just glue them in, hide the dings and keep it period collect!