Very interesting thread!
Looks like Jack Ruby had been arrested at least one other time for UCW before the 1954 report above.
http://jfk.ci.dallas.tx.us/16/1614-001.gif
Edit to add: I used to eat at the Lucas B&B with my dad often. Small world indeed. Seems the club referred to in the 1954 arrest report was a few doors down from the B&B.
Edit to add: Interesting to note from the 1954 arrest report that he only had four shells in the cylinder. Could be some mistakenly carried S&W revolves with no cartridge under the hammer like the old SAA's or does this gun not have the hammer block safety?
Yes it has the post hammer block safety. The Chiefs Special was introduced in 1950 and by that time all Smith revolvers had the safety. But like you said, probably it was done mistakenly. I 've come to realize not all gun shooters are necessarily gun savy.