Good points, and those don't agree with most Vincents, I have seen, either. The hollowing out of the comb sides on the stock, on the other hand, agrues in the opposite direction. Is there no signature on the barrel, anywhere? It could be a very late Caleb gun made, at or near, the end of his life. Not sure what his dates were, but this gun appears to be quite late and shows changes in style, just as Adolphus Drake's work about the same time, show stylistic changes in Bedford guns.
Thank you for showing us this pretty little rifle. You did well to acquire it!
Dick