milford3,
Are you referring to the slight discoloration of the flashing (silvery mirror part of glass at tube base)? If so, then yes.
Can you post a better, ie. higher resolution, photo? I'd like to see a better, clearer image of the area around the flashing. It looks like a white-ish area is forming along the edge of the flashing. This may indicate the tube is gassy (lost, low, or poor quality vacuum) and it will die an early death. Get them tested, if you can, and definitely before putting them back in your amp!
Hope this helps.
