Well, the college itself wasn't named in the book, but it was mentioned that Marcus Brody was the former dean before Grisswald became the dean. In chapter 2 of the book, after Indiana Jones had a meeting with Grisswald, he went to an nearby diner to order something. It is said in the book that the diner is an popular hangout for students, just like Arnie's Diner. The diner is also nearby which also points to Arnie's Diner.
Fair enough but you can't assume that they're the same. It's highly unlikely that Crystal Skull took anything from a book let alone one not available in English. Does it even specify Connecticut? Cause Barnett College is in New York.
It is a coincidence with the diner. As nice as it would be to actually have continuity between the film and a book from ten years before that, we need to go by what the source says, not what we'd like it to be. The wiki is the search for fact not truth. ;)