lets start with my form 1 was approved. now on my form 1 application in the caliber box i wrote 5.56. since i already have a lower with a serial #, model number, and a caliber of "multi" do i also need to have 5.56 engraved onto the lower as well? if so, could i submit a change to the form 1 and change 5.56 to multi instead so there is less machining getting done on my lower? Any help is greatly appreciated. Thank you.