Don't think I've ever seen a metal standard based tube, only on the self centering tubes (octals). Pin 1 is always the heater. Have seen some tubes that have had a sprayed on coating but I don't remember if it has any connection to anything.
Hard to say... Both were 6A7G (glass ST types).. Wont know till i encounter another radio that uses the same tube and see how it behaves in that one...
Meanwhile, its a happy camper with the Philco brand (used) installed...
Steve
Found the old for sale ad on FB for this radio and gathered a couple before pics. And even one pic from the first power up... And of all places to find the proper dial bulbs? A hardware store.. Ones that sell flashlight bulbs is a plus as well. And faucet washers made great tuner mount grommets..
Steve