The size and shape of the bulkhead connector changed a few time over the years. so you will want to be sure whatever you are getting has the same pin count as the one you are replacing.
I looked at a couple in the JY and it seemed to me the type/style/look of bulkhead connector changed but hole in firewall is the same. (IIRC it was moved over some on FW for the hydro clutch MC hole location)
what I found changing my 85 truck harness/steer column was in 86 they changed to a weather proof connection that do not inter-mix 85-86
I ended up changing the 85 harness over to a NOS 86 harness to fix some cut/spice/burnt wires.
and because of the plug style change in 86 I had to have the underhood-main dash- lower frame/TL harness to do it correctly as a bolt on replacement.
harnesses got even more complex with the 88-93 trucks due to the multi function/TS switch TBI to MPI magnum change over. those got a complet harness change also...but my 85 bulkhead connector fit the 91-93 cab I have.
I think the size of FW hole and bulkhead connector size itself is the same but agree the style plug/wire count is the change.
either way a good OEM harness is hard to find around my area and I have started R&R 82-87 harnesses any condition from local JYs to stash for the next 30 yrs.
I sure do find more chopped up/hacked on harnesses than good ones for sure. so having a bunch to unwrap is helpful on repaires IMHO.