It IS regulated by the same laws and agency as a full auto.
Yes, you are required to mark the manufactured item- C&P
- You must mark the newly made NFA firearm with the S/N, Model Name or Number, *your* Name, City, State and the caliber or gauge. If you used the S/N, Model and caliber from the original Title I firearm, then you're already half-way there as far as markings go ...
- Accepted abbreviations may be used for your name (i.e., your ititials), city & state. Ex: John Q. Public, Anywhere, PA can be marked as JQ Public, ANY PA. Trust names may NOT be abbreviated
- The S/N must be marked on the receiver or frame, and must be no less than 1/16" in height and no less than 0.003" deep.
- The remaining information (name, city, state, model and caliber) may be placed EITHER on the receiver OR the barrel, and must be no less than 0.003" deep. There are no minimum height requirements for these markings.
- All required markings must be in Roman letters (English) and Arabic numerals (1,2,3 ...), and be "wholly unobstructed from plain view". In other words, they may not be placed under handguards, grips, inside mag wells, etc.
Forgot- for the paperwork, you need a form 1, and a form 5330.30, certifying compliance wit 922. Besides prints, think they now require 2 passport type photos of you.
See 27 CFR 479.