Going a step further, weights, i.e. coefficients, aren't produced by a person at all – they're produced by machine algorithms. Because a human did not create the weights, the weights have no author. Thus they are ineligible for copyright in the first place and are in the public domain. Whether the model architecture is copyrightable is more of an open question, but I think a solid argument could be that the model architecture is simply a mathematical expression – albeit a complex one –, though Python or other source code is almost certainly copyrighted. But I imagine clean-room methods could avoid problems there, and with much less effort than most software.

IANAL, but I have serious doubts about the applicability of current copyright law to existing AI models. I imagine the courts will decide the same.