American copyright, as opposed to most European copyrights, only protects creative works. Fully machine generated weights are not creative as no human touched them. You can copyright the training code, you can't copyright the output.

There is an argument that it's a derivative work and it's therefore copyrighted under the same protection as the training data, but that gives the rights to the owners of the training data, not the ai-lab. Courts are seemingly mostly rejecting this though as it's different enough to be fair use.