Probably went on an Indian Trade musket. They are the only gun I know of that had a nailed on butt plate.
I guess the trade musket wasn't the only one, I just found a picture of a Hudson Valley fowler with a nailed on butt plate.
Here is a picture.

We would call a "fowler" now days a "shotgun." To me, Indian trade muskets are fascinating, and worth the research. They were cheaply made, and there were several things the Indian customer demanded. One was the gun had to have a serpent side plate. Here is a picture of a trade musket showing the side plate.

And another picture up closer.
