What would the ATF do if aware of an NFA item that was not engraved correctly. An initial instead of a name being spelled out?

Ask that it be corrected or confiscate? Something else?

There isn't really any well laid out case law for this situation, as it is so rarely something that could be discovered even if incorrect or missing.

I can tell you that the penalties written into the law allow them to throw the book at you if they wish, which means confiscation, $10,000 fine, AND up to ten years in a Federal prison...

I can also tell you of a case I vaguely recall where the ATF actually got a hold of an NFA registered item that was not engraved, and they proceeded to crudely electro-pencil or hand engrave the information before returning it to the owner, and no legal action was pursued...

I guess it depends how big an issue you make it.  A random ATF officer happens to see it at a range, might just dismiss it or tell you to fix it ASAP.

Get caught with it while committing a violent felony, then I'm sure they'll love to also tack on NFA violations to your charges.

It is, admittedly, a bit nebulous.

In order to know it is incorrect, they would have to see the gun and match it to the NFA Database to see the filed F4 does not match the gun 100%.

Have you every matched your factory MG, SBR, silencer to its forms? Have they EVER been a 100% match? Right now F3/F4s are being approved for M4-2000s with the MFG "Remington". No city no state, and no name "Remington" on the silencer. And nobody getting in trouble.

I am not a lawyer, this is not legal advice, this is merely my personal opinion, it's worth what you have paid for it-

If the serial # is visible and intact, they can check that # against the NFA database and see your info. John Doe Trust of Anytown, USA- if it's engraved "J. Doe Anytown, USA" I really don't know they'd make an issue out of that.

That said, if they're looking into you for marking violations- you've got bigger problems.