BTW, Jeep, some Hi Powers were sabotaged in the FN plant, Belgian workers weren't real fond of their Nazi occupiers. If you ever intend to shoot it have it checked out unless your father in law fired it a lot himself. It's the unknown gun that is suspect.
I don't know how common this was but something to be aware of. Have a good hunt!
The biggest issue with assembling an AR isn't so much getting the parts together right - it's getting the right parts together.
US Army 1966-69, VFW Life Member, Retired Geek