Was the 21AXP22 the only metal color CRT in mass production??

[rca2000]

As we all know...the 21AXP22(and the "A") is a metal CRT, wherein the neck and screen are glass--but the bell is all metal--and is the anode. MANY BW tubes were this way...but i KNOW that the 15GP22 is glass(most of it, anyway, it DOES have that "flange" behind the faceplate, so it might be considered a "hybrid"), and I KNOW NONE of the color tubes that followed the AXP were metal, the 21CYP22 was glass--and so were all that followed, to the best of my knowledge.

But by the time the AXP was in production--(54-58 or so) metal tubes were already OUT for BW--so WHY was the AXP metal, but not the 15GP22, or any others(AFAIK)?