Maybe the tube experts know what those CRTs are. At first, I thought 21AXP22, which has a metal bell, but those tubes seem to have a slightly narrower, longer bell than the 21AXP22 that was in my CTC-4:
The 21AXP22 also came after the 15GP22.
Regards,
Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html