I can simplify the task, can you convincingly explain how the same model can be produced from this dataset? We can start simple, how you can possibly get the same weights after the first single iteration? I.e. the same as original model got. Pay attention to randomness, data selection, initial model state.
Ok, if you can't do that. Can you explain in believable way how to prove that given model was trained on give dataset? I'm not asking you for actually doing all these things, that could be expensive, only to explain how it can be done.
Strict 'open source' includes not only open weights, open data. It also includes the word "reproducible". It's not "reproduced", only "reproducible". And even this is not the case here.