That sounds pretty accurate. It boils down to being an A student or a C student on the letter of the law. People who work in gov are usually D studentsI'm not going challenge Nonliberal on this as he has probably forgotten more about NFA that I know. However, readily removable in all of the documentation I have read in the NFA applies removing or obliterating a serial. Covering a serial number is not removing it and nowhere does it define readily accessible for viewing just that it be visible. I'd go with engraving the OEM serial number with the NFA engraving and be done with it. As an end-user unless you do something really stupid how often does an NFA agent inspect your stuff. For Nonliberal as a SOT holder it definitely applies more than an end user. Worst case call them up and submit it in the ask the experts for full clarification.