The mounts on the block cannot be upside down because there are two holes up top and one on the bottom. I've tried swapping them side to side.
The mounts on the frame can also only go one way because of the direction the engine sits in the mount. If I installed them upside down, the mounts wouldn't sit on the frame anymore (see earlier picture). Nevertheless, I tried it. I tried swapping sides too.

Tried looking in my LMC catalog, but they only offer one type of engine-side mount
The truck had a SBC 350 in it, and thats what I'm putting back in. Newer one is a 1989, but its still generation 1 small block 350. I don't get it. You're right, this shouldn't be this hard!
Thanks again for all the help