[Boatanchors] Amp Question

[George KB2Z]

This one is a bit off, but would anyone have an answer to why 2x3-500 
amplifiers in gg configuration sometimes have 1,2, or 3 caps paralleled to 
the grids, some have a choke paralleled to the caps?
I have seen same series amps done with the caps and coils and without. As 
an aside it looks like Japanese versions of some of the same amps have the 
grids tied directly to ground. Is it a spectral purity FCC thing? I have 
been looking and cant seem to find the answer.
Thanks in advance, George KB2Z