Ed,
I fully agree with your justification.
Traces of red lead (minium) paint - you sure caught me there! - sounds a lot like 16th/17th century by the latest.
Anyway, I am covinced that you got a very early piece. A tentative attribution to Nuremberg or - in general - South Germany/Austria/The Tyrol (within their historical boundaries respectively) - cannot be generally excluded although that sort of hardy tools was made identically all over Western Europe .
In any case it seems extremely attractive to me! Well done, buddy.
Maybe I should start purchasing my 16th century harquebuses from ebay
Michael