For the first time, I've actually re-tubed a whole TV set, my Zenith C2004/14B38, in part because I was able to get the tubes very cheap (except the 13Z10 and 19VALP4, I'll stick with the old ones).
To my surprise, when I opened the cartons of the three identical 4BZ6 tubes, I saw the code "92-12" on the tubes. I know in the past, that this would be "year-week" on many tubes, as well as other products, but why in the world would anyone be making new 4BZ6 tubes in 1992?
(FWIW, re-tubing made the picture a little brighter and wider, but the problems I had been hoping to fix, intercarrier video buzz and horizontal foldover on the left, are little changed
)