Bullet Treatment

I live right by the Delaware, so this was over the river in PA. I went to a Sports Authority over there that straight up told me they won't even sell firearms to anyone in NJ. Then I decided to stop in Dick's a couple weeks ago while my girlfriend was doing some xmas shopping. The guy was ready to order the gun that day(knowing I was an NJ resident), but I told him I was still shopping around and waiting for my end of the year bonus to come in. Yesterday, I got my bonus, so I excitedly hopped the border and hit the closest Dick's location. I waited a good 15 minutes for some clown to get off the phone so they could call it in, and then the guy goes, "Oh wait, you're NJ and you want WHICH gun? Not gonna happen buddy. That's not NJ legal. Pistol grip, adjustable stock, and it looks like it even has a bayonet lug. We can't sell you this. Move to PA." I was pretty pissed. I was in the new Heritage Arms location in Easton, PA a couple weeks ago for their grand opening and they were ready to let me walk with it. The only reason I went to Dick's was a 50 dollar price difference...which I apparently wasted my time on.

Hey guys, I'm new on here and new to purchasing firearms. I just tried to place an order at Dick's for a Mossberg 590A1 with the pistol grip/adjustable stock. They shot me down and said it wasn't NJ legal. Can someone verify this? And if it is legal, any idea where I can purchase one that actually knows the laws?