New cab mount question

[Blue'72]

I'm researching before I install the new mounts and I think I'm more confused now than I was before. With this kit (COUNTERPART 67-5001) the four cab mounts, or cushions, are different sizes in height. There are two that are thicker than the other two. From what I researched, this sounds like mounts for a 4wd. Also, the core support mounts have a much smaller diameter insert than the holes in the frame. I'm digging through the old stuff that I took out 6 months ago and I can't quite figure out if this is right or not. I've noticed that this kit is a more generic kit than what GMCPaul's carries on his website. I googled the part number and found a few others that carry this kit and claim it is for a 67-72 1/2 ton 2wd. I just can't make sense out of it...