good to see some test gear surfacing Mike,
often a poorly represented part of the kit....far less 'sexy'
The images from the ZC1 club are of an English one I had, I have since moved it on as I have a superb AWA set the same as yours.
here they are as a comparison.
I like the RCA wavemeter only because I separately found the associated spare parts box for it.
The Class D Wavemeter is cool because its clean, complete and the associated photograph. circa 1952 taken at a CMT course in Waiouru NZ along with a ZC1 MkII
Brent