Very informative threads!! Mostly over my head. I simply read the TM's, and followed instructions.
During the almost 30 years of working on army gen sets, I never worried about compatibility, as long as the part numbers on the replacement parts were the same. The NSN is all well and good, but the part number is the real deal. Often, when we ordered something by NSN, the part number was different, the part still worked, but it normally meant it had been a newer, or older purchase by the military. For the ten millionth time, how I wish we had an old copy of FEDLOG. It shows so much info, it's unreal. Type in a NSN, and it will show all compatible NSN's and Compatible part numbers. Not always the same!
The freq transducer/ matched set was one of the few parts that needed to be double checked. And we rarely checked. Simply ordered the part, and put it in. Confirmed the output reading with a multimeter and that was that. Often, someone would get out his handy dandy knob dicker, (small screwdriver) and "adjust" all the meters.
There is a small adjusting screw on all the meter faces. As the needles were almost always below the last meter reading on the scale, these good intentioned souls would adjust the needle to meet the scale, but powered down. The meter would read, but accurate? Not even close.
For most users in the forum, a couple of hertz, or a few volts difference are not going to be a big deal. Once again, that's why the sets are produced in utility and precise versions.