71' Carrier Bearing removal (???)

[kspops]

I just go out from under my 71' lwb Half ton, 2WD, The carrier bearing dose not look to be removable on this truck. (Major ?)
I do see some rivets that hold a bracket to the trailing arm cross member. Are these to be removed for removing the drive shaft? or is there another place to look? I do not see another place for bolts to be holding this thing together. If the rivets are to be removed, I have to start wondering about the rest of the truck (Original Equipment or newer?) Thanks for hte help, Ed