I know that it is possible to use a UN 72 Sealed Cartridge Bottom Bracket assembly with Phil Wood French Threaded Cups in a French threaded bottom bracket shell (An old Peugeot racing frame, in this case). Is it possible to use a UN 71 bottom bracket instead of a UN72? Are there any spec differences between the two cartridge assemblies that would keep the UN 71 from working in place of the UN 72?

Thanks for your help,
Anthony Siracusa