I agree with the others that state you did good not buying it. Too many cheaper options now to assemble your own, even if just by joining a complete lower and complete barreled upper by the same manufacturer. You can buy better triggers, bcgs, charging handles, etc., pretty cheap right now if you are in no hurry and look around. I did just that myself recently.

Big question I would have is what kind of barrel?

Could be anything from a $90 Bear Creek to a $900 Proof Research or Krieger.

I've never bought a build that someone else did, but it would have to be a screaming deal and I would want to scope the bore first, and know every single significant part that was in it.

Barrel and bolt are important.

I'm kind of surprised it took so long for someone to ask that question!

Came up in the third reply. lol

The only shooting I do is casual target shooting for fun.
I have come to the conclusion that 99.9% of manufactured guns, regardless of price are capable of shooting more accurately then I am. Some might need adjustment of sights or tuning but as long as they function properly and are not picky on ammo I am happy.
I know a couple of guys that gun they buy, new or used, have spend a bunch of money for every upgrade they can find. It's some kind of obsession with them.
I would rather spend my money on more ammo so I can my guns.

If I were to buy a complete AR. I'd buy right from manufacturer and not a FrankenAR. That way if something happens I can send it back to the company for warranty work.

If I build my own and something goes wrong. I have the know how and tools to work on it. But if I were to buy a whole rifle. I'd expect someone else to service it for free is something goes wrong.

I checked GunBroker for a complete assembled 11.5” upper w/bcg & ch, found several for $350 … then for a complete assembled lower, several for $250 or less. Push the lower pins through the upper and you have a complete AR for $600 for both parts that would have a warranty.
Keep in mine these lowers all probably have a standard 7 pound service trigger, far from sweet but you could put in a RRA 2-stage for another $120 or so, and have ~$450 for ammo or put towards an optic.e