Seat question

Hey everybody, I was by my boat today and noticed that the previous owner did have seats installed. It was hard to tell but the sun was shining just right so I noticed the creases in the carpet and found screw/bolt holes. The holes go all the way through the plywood and the aluminum. I have a seat swivel and all the holes line up perfectly. Is it ok to screw the seat swivel directly to the boat, then to the seat?
Since there are already holes for bolts, how would you mount a seat?
I already have a bass pro shop swivel and low back seat. I just haven't seen people do it that way I guess.
Thanks!
Oh yeah and it's a Lowe 1436L

Anything?
I guess pretty much what I wanna know is if it's ok to mount the seat and swivel directly to the bench, nothing in-between.

Yep...you can...mine is mounted right to my wooden bench top.

Cool that's what I thought I just have seen it I guess. You think sheet metal screws would be enough?

I did through bolts...it is what the instructions on the swivel recommended...if you can't get underneath maybe an alternative would be a butterfly bolt.