Is this cab mount correct?

['68 Newtricks]

I bought some core support and cab mounts. After putting the cab mounts on and stepping back I noticed it's got quite the rake. Seems like the rear is spaced off the frame farther than the front. It also doesn't seem the bolt's thread is long enough for this rear mount. Just as the rubber starts to compress, the captured nut bottoms out on the shank. I can't move it by hand unless I really really try.

The cab mounts came as a kit from LMC, in one bag, but this just doesn't seem right. The front rubber looks like hockey pucks, the rears look like this....