It was a Shuguang Treasure 300B-Z. I am not really up on tube anatomy but I believe that the grid is composed of wires wound around but not touching the filament?
These did not have the glowing dots. The very bright dots seemed to be on the metal casing that surrounds the grid and filament. The cathode? The other tube just has a glowing filament as one would expect.
I am going to return them as I have low confidence in the "hot" tube.
The vendor has been very understanding.
Yes the grid is a wire around the cathode,
There should be no glowing dots is a tube,
The 300B is a direct heating triode so there is no filament,
the Cathode is heated directly by DC voltage.