Re: New foam or old foam
That looks like styrofoam of yesteryear... Even if its dry, you would probably be doing yourself a solid (safety and longevity wise) by upgrading to close cell. You can use the pink or blue sheets from the big box stores, or you can use 2-part pour-in form (can be purchased from U.S. Composites and other similar places). I re0foamed my boat with the blue sheets for under 200.
Hope this helps...