To add to the tube parade- a brief history of the MOV A1834/CV2523
Earlier, pre 1954 black base A1834. The labels are painted on and can rub off! HK (1952) and JJ (1953) date codes.
Brown (curved) base design starting from 1954 (KE date code). Internals seem identical to the black base so far. Label is more resilient now (right)!
Brown (straight) base. Looks like the cup getter was introduced from 1955 onwards replacing the older rectangular getter. Some time after, the distinctive short bottle design was adopted. Straight and curved bases are both used and do not necessarily indicate vintage, probably depending more on the specific order and desired environment of use at the time.
I don't have any tubes later than 1968, but I'm aware that they switch to the 4 digit codes after Z= 1968 (YYWW). They can then have halo getters (but never flying saucers!)
Nice post and so knowledgeable! Are there enough pictures here to give me some information on these?