I'm halfway though installing some 2002 Silverado Seats in my 75. Got the passenger side in and ran out of steel for the drivers side. No, the bolts don't line up, but you can fab up a bracket to bolt them in. Mine had the the flip forward setup on the passenger side that if I bolted the '02 seat to it, the bottom of the seat would have been 6 inches too high. I ditched the flip foward mounts all together and used some steel, 3/16" X 18 inches (two used, one front one rear)and drilled the holes to match the orginal mounting points. 4 more holes to match the tracks on the seat and some grade 8 bolts, nuts and lockwashers and it bolted in.
I'd take some pictures of it, but can't find my Digitial Camera at the moment.
I took me a couple of hours to put it together and that was with just a hacksaw and a cordless drill that lost all it's juice. Fits like it was meant to be there and with the seat back flipped forward and the seat slid to the front it still has the same amount of room to pass through than the orignial did.