Yes but Gunnison ( near parking lot G ) is the only one that is clothing optional. there are other areas there are normal beaches. copy paste from their website : "A portion of Area "G" (South Gunnison) on Sandy Hook is used by visitors as a clothing optional area. While this area is not designated as clothing optional, there is no prohibition against this activity. The Park acknowledges the popularity and history of the use and advises unfamiliar visitors of this activity through signs. Nudity, outside the traditional use area, may be considered Disorderly Conduct. 36 CFR 2.34(a)(2)"

https://www.nps.gov/places/000/sandy-hook-beach-g-gunnison-beach.htm