Actually, Philco liked to "pot" their capacitors in tar in bakelite boxes - but by 1941 they were using the wax coated paper ones like everyone else. They may have started using rubber insulated wire by then... it's crumbly now - the old cloth coated wire held up better.
The 4 page Philco service bulletin is on my web page:
http://www.audiophool.cjb.net/Philco.html
You'll need to get the DjVu plug-in from Lizardtech.com to view or print it.