[codefox1]

6J5, 6A8 and 6K7 are available and are drop in replacements for the "G" types and do not require shields. The socket for pin #1 must however be grounded to the chassis. Be certain that these pins are not used as a convience tie point for unrelated components. The other remaining tubes, 6K5G/GT and 5Y4 do not get shields. Not to confuse you, but if you need a new 6F6G, you can replace with a 6F6 (metal type,) and if so ground Pin #1 as above.
Actually replacing the tubes may be easier and less of a pain than sourcing tube shields, but it's up to you. The metal tubes are more plentiful and cheaper than the G types.

I trust this is your set: Shoot a picture or two.