Al,
I went out and checked again for the fridge vent you were talking about
under the trailer. You were right, there is a vent screen located directly
under the fridge on my 63 Tradewind. However there is no lower vent or grill
in my 57 Sovereign of the Road or my 59 Ambassador. As Scott pointed out,
his 60 Overlander doesn't have lower exterior fridge vents either. I guess
Airstream or Dometic decided somewhere between 60 and 63 that the fridges
worked better with exterior air as cooling. I think I'll add this feature
to my pre 60 trailers.
Colin