drivers front seat leans back too far

[67ss&99ss]

I am in the process of fixing some issues in my 1972 K/5's interior. When I removed the drivers side seat, I noticed a prior owner had put some wood blocks between the bottom of the seat frame and the floor pan to raise the rear of the seat up. Without a block or spacer under the rear of the seat tracks, the seat leans really far back. Is this a common issue? Upon looking at the factory service manual, I see a "shim" listed to go under the seat track, but I have no other Blazers around to look at for reference. I assume my shims are missing?

I removed the seat tracks from the seats, repaired the one issue which was related to the engagement of the front/back adjustment mechanism and prior to reinstalling them on the seats, I put the seat on a level surface and it does not appear to be bent or warped. I have 1.5" thick steel blocks under the back of the seat track now and the seat appears to sit level.

Any feedback to help me figure out and resolve the issue is much appreciated!