It's probably a good Oly. How a 2003 compares to other brands is up for debate.
Yeah, clean it then go shoot it. If something look funny, first take it to a gunsmith who knows ARs.
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