I doubt that. I think it would have been difficult for TWM screenwriter Anthony Shaffer to have seen Two Thousand Maniacs by 1973, Wicker Man’s release year. The comparatively classier and more respectable The Exorcist was banned in some parts of the UK in ‘74. I don’t see Maniacs getting any theatrical distribution at all before ‘73. Maybe he could have seen it in the US, but I don’t really see Shaffer hitting the Southern drive-ins either.
My favorite HGL flick is Blood Feast, but if you want a film you can take more seriously 2KM is a good choice. Granted, I still think it works more as black comedy rather than horror, but at least the filmmakers seem to know what they’re doing, as opposed to the rampant lunacy of BF.
ETA: Forgive the increased going on at length, but I just remembered this passage and felt I must share. From The Aurum Film Encyclopedia - Horror 1985 edition:
