I built a copy of the kit around 1970 or so-- I think that was the original release - I was 11 or so at the time.
That version of the kit was "Adaptable to sail in water!". The kit included a removable triangular keel, and came with working sails. The sails were some sort of water proof mylar-like material with the seams and panel lines printed on them in a dark color. They looked much, much nicer than the standard vac-formed plastic sails.
The kit was re-released in the late 1980s, in one of those yellow-striped boxes. That version had vac-formed sails instead of the working sails. It still had the (unused) triangular fin keel parts on the sprue.
I had several free-running sailboats way back then, and the America was the best sailing and fastest boat in my fleet.
I now have a copy of the display-only version of the kit. I also have a copy of the original sails in my stash. A seller on ebay was selling the leftovers from a kit-- someone had built the hull and then lost it. I got the masts, sails, instructions, and a box, all for $5.
-Bill