1966?

My old VHS cassette of this short movie includes a copyright date for it of 1966, while an 'Entertainment Weekly' story from a few years back claims it was released in 1967. Meanwhile, IMDB.com itself gives it a release date of 1968 (as does Wikipedia). However, an 'L.A Times' story published in 1998 includes the 1966 date:
http://articles.latimes.com/1998/jun/08/entertainment/ca-57718