Original Rear end type on my 70 Duster

The engine code/trans code just signifies which family of part is installed, not which assy #.
For example, a 69 roadrunner engine code for a 383 would show .... 383. The assy code would tell which 383, four speed magnum, auto trans magnum, four speed with a/c, or auto with a/c. Four different 383s, four different codes on the fender tag, at least at lynch road.
Like I said, I don't have any idea what a hammtramck tag shows (oops, NOT L.A, my bad.)