I wouldn't worry about it too much. Usually if the plate (the graphite part in an 845B) is glowing, that might be an issue. They can run well higher than 200F. More like 500+F measured at the envelope (so even more inside.)
LOL Viridian. You crack me up. I'm not far behind you at "almost" 49, and my hearing is dinged up from skeet shooting as a youngster without ear protection. Loud music and concerts haven't helped. Left ear is definitely deficient.
Ed- what if the plate does glow? Do what? Now, it's just the insulators, and it's both tubes. They have perhaps 100 hours on them. Don't want to blow them up. Will re-bias tonight.