When was the RCA 21AXP22A in use?

[mopalia]

Hi, new member here. I'm cataloging the television collection at the Henry Ford Museum, and we have a 21AXP22A in the original box. The original cataloger claimed a date of 1940-1949 for this tube! I have found references to it in 1956-1959 RCA televisions, but I'd be grateful if someone could give me a better set of dates during which this tube was put into new sets. Thanks!