I used an off-the-shelf (or out of the bucket) barrel and GI slide and no fitting was required. I did have to hand polish one side of the hammer to relieve a slight binding condition, but that was the only hand-fitting required on my pistol. It was not a nightmare to assemble, far from it, and the only thing I needed a gunsmith for was to stake the plunger tube to the frame. I was too cheap to buy the tool for one use.
You don't have to be a gunsmith to build one, and it's possible to build one out of a bag of miscellaneous parts, assuming you can still find all of the parts.
If RIA can make a functional 1911 for $400 (or whatever they sell for), what are you getting in a $2000 Ed Brown? A name, a pretty finish, and probably a little more accuracy. I'd rather put my $2000 to other uses.