Yes, they are worth somthing... but it depends how fast you want to get rid of them.
The going price for a hull with a clean title is about $100. If there isn't a title, then take it to the junk yard. (they may want to see the title)
I sat on an XP hull for about a year, and happened find a buyer. You can put them on ebay for an opening bid of $10 and see what you get.
One thing though. If they are only missing the engines... then you can make a butt load of $$$ by selling the rest of the parts, if they are in good condition. (they are in high demand)
Hood: $75
seat: $65
Guages: $50 each
Pump: $100
Computer: $150
VTS: $150
You get the idea. The parts will go quick this time of the year. I bought, stripped and sold that XP in about a month.