[Amps] Gettering GU-74B's in-place with screen voltage?

[Jim Barber]

Is there any reason I shouldn't getter a set of GU-74B's in-place in the 
amp with blower air, filaments hot, and with grid and screen bias 
applied, but with the plate caps lifted? The amp in question is a QRO 
HF2500DX that appears to be virtually unused, but also appears to have 
been stored for an unknown amount of time.

Most of my experience is with metal-ceramic triodes (which "bang" after 
storage without gettering) and good-old beam pentodes like the 813, 
which don't, or at least haven't yet for me, at least. These (Russian) 
metal-ceramic tetrodes are undiscovered country, so I may be being 
over-cautious. Or not?

Thanks,
Jim N7CXI