[Arran]

The original type #80 tube was a shouldered type or ST style, like the rest of the tubes in your 630, not a balloon or globe type. In reality it doesn't make any difference electrically which one you use, something the audiophools would know if they actually sat down and read a tube manual or knew anything about how an electron tube worked. There isn't any harm in using it as long as the capacitors are in good condition, but should you pick up an earlier AC radio built in the late 1920s or early 30s it would be a perfect match for that.
There was a reason why they came out with the shouldered type envelopes. With a rectifier or other types it didn't matter so much but with audio tubes you could end up with microphonic problems because the elements were free standing and only supported from the base. This what I find silly about the so called audiophools, they claim that they want "perfect sound" but they insist on using tubes with an envelope design that makes that impossible.
Regards
Arran