FYI:
As per federal law:
• If it has a barrel under 16”, a brace instead of a stock, and it is under 26” overall length - it is a pistol* and does not require a stamp.
As described, your gun manufactured by Radical would be illegal in NJ.
• If it has a barrel under 16”, a VFG, a brace, and it is over 26” overall length it is an “Other” or “Firearm” and does not require a stamp.
• If it has a barrel under 16”, a VFG, a brace, and it is under 26” overall length it is an AOW and requires a stamp.
• If it has a barrel under 16”, and a stock, it is an SBR and requires a stamp.
Welcome to the wonderful and confusing world of AR pattern carbines!
*note: A pistol can not have a VFG by law, that makes it an AOW which requires a stamp. You can put a handstop (like the Magpul AFG) on a pistol however.