Reno
The comments as to the "Nema-1" enclosure got me thinking...I'm not sure I've ever seen an enclosure of this vintage that would meet any sort of "outdoor" spec.
I agree there may have been no NEMA 3R standard at that time.
I still would think outdoor units where available or that this one says something about dry location use.
But who knows, it's still working it must be OK.
Bob