I mean that I normally expect to see the tops of the pre-amp tubes silvery-looking from the metallic coating on the inside:
View attachment 398715
Maybe it's just the picture, or maybe the getter is placed somewhere not in view, but I don't see it on most of those tubes, they look either frosty or translucent:
View attachment 398718
The two on the left I can kinda see it:
View attachment 398721
I'm probably preaching to the choir, but if the getter is gone or frosted my understanding is that it indicates the tube vacuum is compromised or soon to be. Maybe it's just the dust.