Yep its all foam under there. I have an '88 H-200 with the same hull different top cap because its a bowrider. The deck rotted and I had the whole thing out, repaired and put back together about 7-8 years ago. Big job. To answer your question no its not practical to take all that foam out unless you had to do the same thing I did.
https://www.dropbox.com/s/e316zo94sig9y ... r.jpg?dl=0https://www.dropbox.com/s/v24fgzc4yvwm6 ... W.jpg?dl=0https://www.dropbox.com/s/pes4wf5zt63mx ... n.jpg?dl=0https://www.dropbox.com/s/ds48pon6ov5tz ... 1.jpg?dl=0Best thing you do is get rid of the carpet, get rid of that glue, inspect the deck, if its solid, re-glass it and then gelcoat it in non skid gelcoat. Seal every hole used to mount the seats. The carpet is what holds in moisture and the rot starts in all the unsealed holes. They also used hundreds of nasty rusty staples to hold the deck down, I glued it with 3M 4200 and used stainless wood screws that were all sealed in then glassed over.