Way to go Mark! Good find.
We had 2.6 density foam put into all of our cushions in '95. They still sit and sleep without "bottoming out".
( Doncha just hate it when the boat you are delivery-crewing on has old flat cushions for your two hour off watch attempt-at-sleep?
Our replacement ones were noticeably a bit heavier than the factory stock stuff we threw out.
The prior owner inadvertantly did us a favor by letting mold and mildew grow throughout most of the foam........ ick. Much laundering of covers was involved and we did save them.