According to the above information, the Sandia Crest Local Mail was in use during 1956-1957. Anyone know when it ceased operation? I assume it is a long closed operation.
Actually, I was a bit intrigued by the Sandia Park, NM postmark (from the US Post Office) and started to look up the location on the internet. In the process, I came upon this photo (although partially blocked by a stop sign) suggesting that the Post Office for this location has the unique distinction of serving two locations -- Sandia Park and San Antonito -- and both towns using the same ZIP Code!

I don't know how old the above picture is, but it can't be that old with the new USPS logo and the 9-digit ZIP Codes shown on their sign, yet a search of the USPS web site does not recognize San Antonito, NM either by ZIP Code or post office location, so perhaps it has recently become a "discontinued post office" and Sandia Park, NM has taken it over entirely?
I also did a USPS search for Sandia Park, NM and surprisingly, Cedar Crest, NM post office came up as being closer to that town than the Sandia Park, NM post office!

Admittedly, I know nothing about the geography in that area but do know that they all are reasonably close suburbs of Albuquerque, so maybe there was just some consolidation of post offices in that area.
I have never before seen a location where the same ZIP Code was applied to more than one town, though.
Maybe someone from that area of the country can explain it further.