Welcome to the frustrating world of trying to figure out old billiard stuff.
Here's an interesting case. I have this set that's brand new called Brunswick "Century" balls. Made by Saluc, can't find them in any catalog. My guess is they were only sold through dealers in display cases, cheaper than Centennials. Cue ball is white blank.
I'm guessing 1960's based on the Courier typewriter font inside.