Yes a 639, and a fat finger.
I've have the schematic, but no indication of insert/remove direction. I'm searching for instructions now, nothing found so far. It must be so simple and easy no one has asked before. I suspect I should drive pin from the flat end. The rounded end is likely rounded to help it past the mainspring plunger which will seat in center of pin once in place. I worry that the hole on one side may be smaller than the other. I can't recall which end I drove on the 1911 some years ago.
Where is it written a man shall have but one gun?
Though our WANTS are many, A man NEEDS few things, A loin cloth and a knife come to mind, and I'm not so sure about the loin cloth.