Sets that used the first RCA in line tubes could cause distortion
on the bench if close to another set & almost back to back.
On the sales floor portables were crowded side to side,
on top of consoles or on a 6 19" display. No effect seen there.
Only effect you may see would be purity but that would go
away with a few cold starts.
In other words not to worry...........
73 Zeno
LFOD !