Do you have two metal rails like this 2002 B&B that the seat mounts to?
If so you position the seat where you want it and measure (or guess) where to drill thru the figerglass seat bucket so you hit the metal rails.
In this 2002 model the metal rail is about and inch above the floor. I was able to use 1/4" bolts and put the nut under the rail. I did have to use tape to hold the nut onto the open end wrench till I got the bolt started.
On the back two I used self tappers. I did use fender washers on all four.
Sometime you can pull the carpet up and re glue it later.
Dwight