UY1 and Z81 RPOs - question (camper stuff)

[jocko]

Curious about these 2 codes -
UY1 is camper wiring, provides that funky little connection on driver side outer cab.
Z81 is Custom Camper equip.

While I can see how UY1 might be ordered separately (i.e. I have seen a truck with ONLY that option, no Z81), seems odd that one would want UY1 and not Z81. Most likely a slide-in camper vs. trailer wiring thing, etc. Dunno.

BUT, I alwasy thought Z81 included UY1. So, have also seen a truck with UY1 and Z81 on the SPID.

Wouldn't Z81 have included UY1? Or is it entirely separate wiring? I am assuming the latter - simply because have seen Custom Campers with NO external cab UY1 connection port.

Interested in your thoughts.