This is going to be a killer build.
Comparing your 90 with my 91 it looks as if your frame must have gone back to the factory for the usual seat tube work and reinforcement on the chainstay? Did they also add the seat collar sleeve with bolt? They did this to my 91, sort of wish they would have left the bolt thing off so i could run the original collar.
Anyway black on black=rad
I'm not really sure on the details, as far as I know it hasn't got the seat tube mod, but the little chainstay reinforcement is there. As for the year, I'm only going off what the seller told me and I think he is going off what the chap who sold it to him told him! If anyone knows how to read these frames better than I do, I'd be interested to know how to date them accurately, if that's possible?! This one doesn't have the seat collar sleeve and bolt, I have a repro YETI clamp for it, but for some reason it seems way too small to go on.....
Bontrager Rigid Fork - All types!
Bontrager Road Lite - Size M or L