I agree that it is not possible to prove if any one specific conversation (or derived RL tasks) was key to solving Navier-Stokes (at least without massive resource expenditure).

I don't really understand how the quantity of training data/rollouts used in training is relevant to the question of whether or not it was trained on these conversations.

I also don't really believe that whether or not this model was trained on these conversations is unknowable information.