Did '76 Topps wax packs have '74 wrappers?
 

Years ago I bought 6 1976 Topps wax packs. Today I happened to notice that a couple of them have mail-in offers on the backs that expire 10/31/74. Some of the '74 & '76 wrappers are identical with "All 660 cards in one series" notation on the front. Do I actually have a couple '74 packs or are they '76 packs in '74 wrappers? Can't tell through the wax paper what cards are inside.

Yes, some '76 wax packs did have '74 wrappers.

i would also confirm that