Just picked up a BRN-4 lower from Brownells and plan to have it laser engraved to somewhat match HK's normal looks (shocker, I know). My question is, what's the difference between marking the lower as just a 416 v. a 416D, and which would be more applicable to my case? Assuming I proceed with the markings from the attached photos would I be "clone correct" (ie. marks on both sides of the magwell, serial number above the trigger, and safety selector markings)? And just to make things interesting before I go spending my mom's credit card again and at the risk of being kicked out by my girlfriend, would 416 lowers only accepting USGI and gen 3 PMAGs be an accurate statement?