Joe,

Welcome to the forum!

Your Motorola uses a 21AXP22. This tube was first introduced late in 1954, and was used in new color sets up to 1958. It has been out of production for many years, and tube rebuilders stopped rebuilding them a couple of years ago. The information you received about the tube still being available new is absolutely false.

That being said, however, I have seen at least two NOS (new-old stock) 21AXP22s on eBay in the last six months. These are unused tubes that were manufactured 25 - 45 years ago and are still good. They have been going lately for $600 - $900. If you see one and have the money to spend, I would grab it.

The 21AXP22 is a metal shell tube. You said that the tube in your set has been replaced. It's possible that it was replaced with a newer all-glass type, the 21FBP22. That tube was introduced in 1960, and a larger quantity of those were built. However, it is also out of production, and not being rebuilt anymore.

For lots of good information, see the following link:

http://www.earlytelevision.org/

Good luck with the set. It is one of the rarest early color sets in existence.