Barney Shore's haircut was unacceptable in the U.S. Navy back when this was filmed - even for a submariner.
The Bigfoot footprints on the dirt are raised and obviously cast and placed on top of the dirt, instead of being deep indentations, which is what someone's heavy walking in dirt would naturally result in.
While the sailplane used is indeed a high-wing Schweizer SGS 2-33, the drawing we first see looks to be a mid-wing SGS 2-32. The SGS 2-32 was utilized in, and won many, competitions as 'Singapore' Eddie Malone is said to have achieved, but the SGS 2-33 is strictly a training aircraft.
In one scene, Tattoo is in Mr. Rourke's office reading stock values from a ticker tape machine, a system that was completely obsolete and no longer in use in 1978.