Gen 2 G22 LE trade-ins used to go for $300-350. I picked one up a couple years ago and no issues at all. CCxxxx serial no. I think there was a frame problem with some E series Serial numbers. I'd expect a G23 would go a little higher today.
If it doesn't have finger bumps on the grip it's a Gen 2 since there never was a Gen 1 in 40S&W.
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