You only found a few? Then it sounds like it hermaphrodited. This is generally due to extreme stress. Plant thinks it's the end of the world and is up to it to repopulate the species, kind of thing.

If you aren't picky then the seeds are good. BUT the wont be the same genetics as the original. If you were growing an F1 grapefruit (first generation from two pure bred parents) then this would be an F2. The seeds though carry the hermaphrodite trait that it got from the mother and I dont see why you'd use them when you have the clones.

Hope that helped.