If you read about me finding 12AB5 tubes that were relabeled 7061 tubes, this may be of interest to you. All US made tubes have a manufacturing code on them designating who made the tube. Some of those name band tubes may not have been manufactured by the company indicated on the label.
101 = Admiral
111 = Amperex
125 = Bendix
158 = DuMont
162 = Eimac (Eitel-McCullough, Inc)
169 = Electronic Tube Corp
188 = GE / KEN-RAD 188-4, 188-5 (KEN-RAD factory), 188-20 (NY)
210 = CBS Hytron
231 = Machlett
247 = National Union
260 = Philco
274 = RCA (Radio Corp of America)
280 = Raytheon
310 = Superior Tube Co
312 = Sylvania (Hygrade Sylvania Corp)
322 = Tung-Sol (USA)
323 = United Electronics
336 = Western Electric
337 = Westinghouse
343 = Zenith Radio Corp (CRT’s)
423 = Nortn American Philips Corp
713 = Taylor (aka Cetron-Taylor)
722 = Sylvania-manufactured for OEM equipment makers (Allen Organ)
738 = Lewis & Kaufman
749 = National Electronics (also Cetron)
771 = Penta Laboratories
781 = Vacuum Tube Products
809 = Varian Associates
879 = Litton Industries
935 = Electrons, Inc
1022 = Fisher branded Mullard/Telefunken/Amperex
1109 = Raytheon (Japan)
U.S.A.3 (found on the glass envelope) = Tung-Sol
8I = Toshiba (Tokyo Shibaura Electric)