[Milsurplus] CU-1388, CU-5069 couplers?

[Jason White]

Hello list,

I'm busily making a home for an R390A and thought a perfect 
accompaniment in the rack would be one of the older period multicouplers 
so I wouldn't have to swap inputs from my various receivers with 
switches. I've found lots of web pages on the CU-1388, CU-5069, and 
CU-1020 from as recent as two years ago that suggest these were readily 
available for very reasonable prices in the surplus market, but as usual 
I missed out. Are these things now scare as hen teeth?

73,

Jason White
N1XBP