You are not required to notify ATF if moving in-state. That said, it's probably a good idea, so that the registry is kept up to date. You can either write them a letter including your info, the particulars of the NFA items that are going with and where they are going, noting that it's a permanent move, or you could probably just use the 5320.20 and fill that out. You wouldn't need to wait for approval though. Approval is only required for interstate moves involving MG's, SBR's and SBS's. (and maybe DD's, but I'm not sure on that one)