Kook, you are right, you "should" be able to install the parts painted. I mean,just a few hours ago I assembled a 2004 Pontiac Grand Prix ("T" boned by a **** truck, ouch) And of course you "can". I just look at the "odds" with a home hobbyest and that sort of thing. But you are right. I just find that unless it is a show car you can avoid a lot of problems.
SoTxBoTi, read the tip number Five! It supports what Brian laid out. It is a very, VERY hard lesson learned.