Quoted from AlexF:
PBR nor the Williams manual have it correct. The drop front Williams cabs definitely used 25" in front and 28.5" in the back. I have had a few of them and the lock down bar height lined up correctly with other eras and manufacturers with correct legs.
If the 22" & 18 1/2" listed in the documentation is an error it's one that's repeated in the 1969 catalog. Some of the games in that catalog list four 22" legs, others list shorter in the front.
How do you tell definitively which legs the factory installed? You've mentioned, "I have had a few of them and the lock down bar height lined up correctly with other eras and manufacturers with correct legs." How did you determine what lockdown bar height was correct? Did all manufacturers standardize on a specific height and if so where is this documented?
I'm not saying you're wrong alexf , just looking to source factual information for future readers of the thread.