a/c selector switch source for 1979 GMC

[vwjunkie53]

Hey guys,
I'm looking for the A/C selector switch that mounts to the back side of the climate control panel on my '79. I called a couple local parts stores and got the part number out of their old acdelco catalogs, its a 15-71522. Its shown as NLA in their systems. I checked LMC and Classic Truck parts in KS City. I don't know where else to check if anyone has any recommendations that would be helpful. It only fits 77-82 from what I have found. LMC and others show the 83+ switch which looks very similar. Does anyone know if it will back fit with some modification or rearranging of wiring? I have found calling LMC isn't helpful if your looking for any kind of tech info...lol

Thanks,
Jason