✅ SOLVED Musket butt plate id needed

[DownNDirty]

I found this butt plate today next to a large plantation that dates back to the late 1600s. The front side has the number "94" stamped on it. On the inside is stamped a backward "55" and what looks like a "C" and a "U." Also, notice the notch on the right side-possibly to accommodate a side plate?

 

[Z.K.]

Great find and restoration, and very cool expertise on display.