cab mount locations

[xman]

I am getting ready to replace the bushings on my wifes 72 longbed
I have found the front mount location under the carpet but I can not find where the rear bolt comes through. Do I have to remove the gas tank in order to find / remove them ?

Also what have you guys used to remove these bolts (besides a torch)
sinnce they been on the truck for so long.

Any suggestions on this and maybe a pic of where the rear mounts are would be appreciated

Here is a pic of what I am working on