Turned the table over and soaked the working parts in gas over night, and voila! it turns, however reluctantly. I'm thinking it should free up with some use.
Put in the new air cylinder, after finding out that the Bellows company seems to have used some thread pitches not listed in the charts of standard SAE threads. They also installed a set screw in a spot that requires a good deal of disassembly before it can be either seen or reached and in a spot where attempted disassembly will cause damage to some fairly important threaded parts.
The new cylinder moves the table fairly easily with only 25-30 psi air which means only 75-90 lb force. a smaller cylinder will do the job, say 1-1/5" dia running at a modest 50 psi.
That brass pipe sticking out the center is the air supply to the little cylinders on the top. Unfortunately it hangs down a couple of inches below the bottom of the table and over the years it has been bent and banged up. I will need a banjo fitting for that at some point.
Still have no idea how the top is supposed to be removed from the bottom, and there is no indexing mechanism to set the table after each rotation. Oh well, some assembly is required.