Do these go all the way back to '54 ?
Sencore CG126 & RCA WR64 Color Test Pattern generators

I don't know the earliest production. I assume that version or one like it, was produced to equip their color TV repair dealerships for '54. I've never seen or heard of any earlier version of the color bar generator, so I'd guess that's the earliest basic model; maybe with a few updates between '54 and whenever they went to the next generation Chro-Bar II.

Charles

As far as the RCA unit, that's the WR-64. I have the WR-64B and the WR-61A. I believe the 61 is older than the 64. I think the 61 might have been the first. I'll put up a pic of the WR-61 later, it's color bars only, it doesn't also do the dots and cross-hatch pattern you get on the 64.

yes they do.