"registered machinist blueprints?"

I have been told by someone that they hold “registered machinist blueprints.” They have supplied a print #.

This is apparently separate from a patent, but the implication seems to be that it offers some kind of legal protection against another manufacturer copying the product. Is this the case? If so, where can I look up/verify the existence of this registered print #?

Mods, just so we’re clear: I’m not seeking legal advice here, I’m simply asking where to find info.

Possibly it just means that there were a limited number of copies made, each numbered & registered as to who that copy was given to. It’s a method of keeping trade secrets secret, at least for a while. And if the secret does get out, this may make it easier to trace the source of the leak.

I’ve worked on computer systems where we had preliminary copies of a manual released like this – a small number of copies, each numbered, and they registered which number was released to which person. There was also a rumor that there were minor variations on some pages in different copies, such that if a xerox was made of a copy and given to the enemy, it would be possible to figure out whose numbered, registered original had been copied.