On a 93 top gun are the bolster lagged bolted or do they have a bolt and a nut you have to get to in order to remove the seat base.

Both... some are lagged into the stringer and the others have bolts and nuts, mark them properly cause if your tanks are below as in older years, the laggs will go through the tank if you mess up

On mine, there were "sister" plates holding nuts glassed to the bottom of the floor and sole. Take your time and use plenty of penetrating oil to loosten them up.