I got the vaccination in the late 60s and thought I was immune as well.
I'm sitting on way too many now but they do get dirtied up on a regular basis. I'm receiving Christmas cards from Federal 3 times a year.
Well you know me... my first love is always gonna be wood and steel. But it's just fun to put one together. And having it work, especially in my case, right off the bat was a big bonus! Granted they've been really simple builds. Haven't put together an upper yet. Might need to get an armorer's wrench after all. I did get a cheap one, and the nub on the castle nut wrench broke. I figured it broke at approximately 40 lbs. so I called it good.