Convenient eh?
Tucking tubes under the chassis wasn't that uncommon back in those days. Motorola eliminated the need for a cage by putting the 1B3 underneath along with the flyback. Du Mont model RA 103D has a 6AL5 sound detector mounted under the chassis, while Crosley's clone of the RA 103D, with different tuner arrangement, put the first video IF tube underneath as well!
They can, after all, be mounted in any position.
