I found this when googling the same question ("are hollowpoint bullets legal in New Jersey")...
mind you, it's only a googl'y searched answer, but it at least conforms to exactly what was told me by the gunshop:
The State of New Jersey does ban hollow-point ammunition -- sort of. It's legal to purchase it, bring it home, take it to the range and practice with it, bring any extra back home, etc. What isn't legal is for any of the very, very few individuals who hold carry permits in the state to carry firearms loaded with hollow points. Retired police officers (who are the only people who are routinely issued carry permits) cannot carry hollow points. Obviously, this means that they are carrying ammunition more likely to overpenetrate (and hit the baby carriage on the next block, for example.) Active police officers use hollow points on patrol, just as most police officers elsewhere do.
The ban may exist because the state legislature was confused about the difference between hollow point ammunition and armor-piercing ammunition. There is precedent for this thinking: the legislature banned slingshots. They thought that the language in the bill banning slungshots was a misspelling, so they corrected it, making Dennis the Menace into a felon.
Hollow points are on people's minds at least partially because they were featured in the Sopranos episode two weeks ago. There was lengthy discussion of the illegality of the hollow points, but it did not make clear that it was a law unique to New Jersey.
I feel better at least hearing it from a second source. I just wish the law itself was easier to read, given the ramifications of being wrong.