BEWARE OF FAKE JAWS INSERTS! They usually appear "minty white" like new and have been sold by the same unscrupulous sellers since the mid 1990's. The quality is fantastic. This is because they are unauthorized restrikes printed by NSS in the mid to late 1980's (long after the film was in theaters). These "minty whites" are starting to age and in some cases are no longer bright white, and if not looked at very carefully can be mistaken for an original.
There are two kinds of originals, with and without the PG ratings box. The version with the ratings box has no known convincing bootlegs, the version without the ratings box is the one that has a minty white knockoff.
The fake insert has cropped artwork. In the original (without the ratings box) the shark is "longer" and you can see a series of more bubbles on the lower right. Also, most of the fakes have a "hair" - flaw that is to the right and below of the swimmer.