The proof marks are post-1813 so something else is going on here. Either there was another Oaks — which is entirely plausible and the business continued on after Mr. Oaks died or it's a B'ham made contemporary "fake" although I use that word guardedly. Practically all of the name related data we have from this period is based on city directories which, while good, are not infallible. Participation in a directory was voluntary and cost money and by no means did every tradesman go to the trouble of being listed. Also, heirs sometimes carried on a trade, using a name, for years after the original tradesman died. This would be especially true where the actual products being sold were purchased on the wholesale market and simply marked with the name of a tradesman... like this pistol which is almost certainly a product of the B'ham trade. In as much as can be told from photos, I think the gun is fine but the dating is off.