I didn't know about this
http://en.wikipedia.org/wiki/Community_design, I don't know enough about it to know whether its relevant anyway but I suspect the part wouldn't be covered due to the age anyway.
As always, you'd need a lawyer to know for sure. And even if there was one on here I doubt he'd put his neck on the line to give out free legal advice (my friend who is a property lawyer sometimes prefaces fairly colloquial emails which touch on legal aspects with 'this doesn't constitute legal advice).
If you ever make enough money out of it that someone is likely to come after you then you can worry about it then
