I'm pretty sure there were others on those stickers that they used to put on the shrink-wrap around LPs. But all of mine are long lost to the ages. I can't recall another where it was printed right on the album art, but I may be forgetting.
Exactly what Schiffy says. I guess the marketers feared that people wouldn't buy the album because they figured it'd be more of the same.
In the case of other sequels, well let's face it—there aren't many sequels that were big soundtrack business in those years. Possibly just Star Wars; and The Empire Strikes Back soundtrack was marketed substantially off The Imperial March rather than the familiar Star Wars theme.
Also, Jaws was sooooo identified with those two repeating notes, I'm sure many laymen would have even questioned why to buy a full album of just those two notes, never mind a second album of just those two notes.
