To delve into the question at hand, the answer might be more difficult than first blush indicates. Engineering drawing and specified manufacturing processes are always protected by contract. Rebranding is only legal if an agreement is made with the originating entity - not the manufacturer. Of course, treachery abounds. But, it is very unlikely that a factory engaged in a contract with a large, well paying, sponsoring organization would produce "knock-offs" for much smaller concerns and if they would you can be assured they would go to great lengths to ensure the smaller entity never breathed a word of it. In other words, the manufacturer would simply cut the piggy-backer and refuse to even answer their phone calls regardless of how much or how little of the contract was fulfilled. Now, of course, I'm talking about factories that actually have quality standards. That's really the defining factor. If quality is not at issue then anything can be produced in any quantity and no one would fight anything unless the inferior product began to affect the reputation of the genuine article.

So, in short, if a frame is being replicated without a rebranding agreement (or other such on-record permission) then nailing down exactly who is producing a replicated item is going to be difficult. I'm no lawyer by any means but I have been part of such manufacturing agreements and am aware of the generic processes.