Interesting. Well I am happy to announce that this machine has been saved! Looking for information on my new/old dishwasher and I stumbled on a picture that looked very familiar.
I bought my first house earlier this year and this was the first piece I bought for it. It inspired me to build a full 50s kitchen around it. The sink casting is dated 9/58 and the water valve looks to be dated 2/59, so your guesses seem spot on. The dishwasher inside is absolutely mint. It was supposedly never run and truly looks it. The door detail is crisp. There was still original tape holding the rack flaps up. The disposal is a Waste King and seems to be from the same period. I can get better pictures as it sits now.
I got it all hooked up and went to test. Everything seems to work except I've got no water. Shifts between modes, motors humming, heater running, but no water. My first thought was the inlet valve being frozen. Luckily the exact valve is still available new. I could probably rebuild it too. Any other thoughts you guys might have if that's not the issue? Thanks!