OK, the four holes formerly for the chair remained open on the bottom, and a depth check shows it 2 1/2 inches floor thickness.
My 2006 model 2350 floor appears to be 3/4 plywood, 1 1/2 inch foam, and 1/4 inch corrugated black plastic sheeting. (top to bottom)
I did use 3/8 x 4" carriage bolts for the right side, looks like similar for the LP Tank and genset mounting.
Happy Flooring!
