Allow me.
A stripped AR lower, when purchased commerically (internet, gun shop, your favorite FFL) will always need a NICS check and a Certificate of Eligibility.
If you find one online, that retailer will send it to your FFL for the transfer. Your FFL may have them in stock as well.
The parts (LPK or lower parts kit), the upper, barrel, stock, magazines (15 rounds max) and any other misc. parts can be bought without any transfers or visit to your FFL and will be shipped directly to your home.
One thing to remember is that the summary of parts you purchased does not necesarily give you a NJ legal gun. For example, a barrel will need to be legalized with a device that will not add a point on the "evil feature list".
Same goes for a collapsible stock. You can buy them online. But, when assembled on the rifle, is an evil feature unless properly modified.