If they are riveted, there is no need to post photos of the H-M setup.
So, in answer to your question, "Was there two different cross-members for the 1954-1955.1 truck ?", there was only one 1954/54st 31xx rear engine cross-member for manual transmission trucks.
Most likely, whatever is attached at the cross-member mounting point will have to be removed. Do the rivet holes in the frame match the holes on the replacement cross-member?
