[Arran]

 Philco often used to swap tube types around through it's different Code numbers and production runs, I don't recall hearing about Philco swapping a type #80 rectifier for a 5Y4G in one of their 1937 sets though. In something like a 37-660 or 665 the rectifier would have been mounted atop the power transformer so I don't know what someone would have had to do to replace an octal socket normally mounted there with a four pin.
  As for the shadow meter and the dial hardware, I think a donor chassis may be the best bet, though they would not have to come from another 37-665 most likely as Philco used to use the same parts across multiple models.
Someone may even have what you need on here on a junker chassis or from a trashed set that they parted out, the original service folder should have the part numbers so you can tell what is what.
Regards
Arran