correct me if i am wrong, but isn't their methodology only able to recover the number of compute units the chip has?

they even admitted themselves:

but we confirmed on a physical MI300X that, limited to 152 or 148 of its units, it reproduces the layouts we associate with Blackwell, so the layout alone does not settle the question.

they did then add they may be able to differentiate by numerical difference in calculation, but that approach was inconclusive for many of the models.

could also be domestic chinese GPUs the researchers had no access to.