76 K10 body mounts

[76stepsidechevy]

I have a 76 stepside that since I got it the body lines have never really lined up correctly on so i decided to look into it a little more and do something about it. It almost looks like there is a 1" body lift on the truck as theres steel spacers as well as rubber mounts. Is that factory? they're big chunks of steel not the plastic or aluminum blocks that usually come with a body lift.

The bumpers line up and I dont see any relocation brackets. It seems the back of the cab sits low (im guessing the top of indentations in the back of the cab should sit just about even with the top of the bed on a stepper?) I bought a new set of poly body mounts for it and im working on getting them in there right now but something still seems a bit off. I can make or get spacers if it have to but I guess I'd like to know what should line up with what between the cab and bed. Not as easy as a fleetside where you have the bodyline right there.