In any case, Pakistan has never tested any uranium based weapons, the only ones they could have for sale now.
I remember the claims and counter claims over the yields and materials used by the Pakistanis. The plutonium-trace analysis had been disputed by US agencies themselves and I don’t think the Pakistanis would have been dumb enough to burn off their stockpiles in a few hours.
Regarding seismic readings, even that has been disputed.I’ve heard the same about the Indian and North Korean tests and Chinese tests earlier. And it’s not like seismologists are in agreement on these.