[Amps] (no subject)

[George KB2Z]

Good morning all,
I'm new to the list and had a couple of questions that have been bothering 
me for awhile.
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, some are tied directly 
to ground?
I have seen schematics of 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. ( HL-2k)   Is it a spectral 
purity FCC thing?
As an aside, The Japanese HL-2k schematic shows a choke in the filament 
return and the US version does not. I'm guessing the choke is for balancing 
but cant figure why the amp with the grids directly grounded has the 
filament choke(Japanese) and the floating grids (US) dont.
I have been looking and cant seem to find the answer. If someone could 
comment or suggest a place to look for the answers it would be appreciated.
Thanks in advance, George KB2Z