Would there be some way to “launder” the model to make it plausibly viable for commercial use? Train a new model with the weights of this model with some kind of noise added to make it hard to tell what it is based on?
Honestly though, even if you just finetune it, which you will want anyway for any serious commercial application, it's essentially impossible to determine the origin.
I guess in practice, it’ll look suspicious if you have an identical model architecture and have similar performance.