What it reminds me of is an obsolete military arm that was cut down for the use of the native populations in places like Africa.
Similar arms, only in flintlock, were sold by the thousands to native American Indians in the 19th century and are typically found in similar condition. The general condition of this arm strikes me as one that was used much, and cleaned/cared for little. The wire band on the stock looks primitive enough to support this theory.
As to the numbers and/or dates it carries, I would think that they are most likely some kind of importers stamps placed on it when it was brought back to Europe.