The 69 may have it as it was used in house wring into the 70's. There is nothing wrong with the wire it's the connections that cause trouble. I changed out my plugs in the 67, with Al compatible plugs and used contact grease on the connections and have no trouble with my wiring. I would not be afraid to buy a trailer with Al wire, in fact I would use the fact to get the price reduced .
I would love to have a 69 Globetrotter, not many of those short wide trailers around.
Doug & Terry
VAC - TAC ON-1
60 Ambassador Int.
56 Flying Cloud