I bought my regular set from Renata Galasso that year, so I wasn't buying packs (and promptly used a black marker on the checklists

). However, I am fairly certain that the regular size was the only one available.
I do recall for either that Halloween or for Halloween 1976, that whatever packs were included in mixed candy bags (Woolworth's, grocery stores, etc.) were 1975 minis, as I did get a couple trick or treating. I believe the reaction was: "What the....?"