So I'm about to send out my lower and just wanted to confirm the requirements. 7.4.2 of the NFA handbook says the caliber is required in addition to the other info. Is that correct? What if the lower is already marked Multi Cal? So I would need to engrave? ABC NFA TRUST CITY STATE CALIBER I thought only the Trust Name, City and State were required? Do I need to put a comma between the city and state? Any guidance would be much appreciated as this is my first one.