Do you need to engrave ATF Final Rule 2021R-08F approved firearms?
If the SBR equipped with a “stabilizing brace” is registered by May 31, 2023, the possessor is allowed to adopt the markings on the firearm. The maker’s marking exception is only applicable to firearms that are registered pursuant to the final rule. If the firearm is a personally made firearm, the possessor must mark in accordance with 27 CFR 478.92 & 479.102 prior to submitting the E-Form 1.
Source: “Bureau of Alcohol, Tobacco, Firearms and Explosives.” Once the Firearm Is Registered, Am I Required to Mark the Firearm since I Manufactured a Short-Barreled Rifle (SBR)? | Bureau of Alcohol, Tobacco, Firearms and Explosives, https://www.atf.gov/firearms/qa/once-firearm-registered-am-i-required-mark-firearm-i-manufactured-short-barreled-rifle.