It looks like you got one of the nice ones. The all USGI guns with the commercial receiver are excellent as they started with good parts. The parts alone are worth a bundle now days. The box and tags definitely help add to it.
The problem with the Fed Ord guns is you have to know what you are looking for to know if it's a good one or not. The early guns are usually pretty great with all USGI parts and good to go. Yes, there can be minor fitting problems that can be addressed by switching out the problem parts. It's later guns when USGI parts started drying up that Fed Ord was sourcing from all over the place. I'm sure they have problem parts that they force fit together as well when parts started getting harder to get.
I have always loved the M14 rifle. I currently have a Norinco that I got for a decent deal, it came with a USGI stock & trigger group assembly. I plan on doing a Blackhawk Down clone but running a 3x PA Prism instead of an Aimpoint (my astigmatism is bad).