a blatant yahtzee clone going unknoticed with a black dice but a red set oh woe begon ;)
Pretty much, yes.
...as it shares ancestry with other roll 5 dice games...
Hmmm ... Aha! Newsflash:
See this:
http://en.wikipedia.org/wiki/Yahtzee
(read the history section)
and:
http://homepage.ntlworld.com/dice-play/Games/Yacht.htm
The original game was based on Yacht, which was in turn based on Generala, both of which may be public domain (at least I see nothing to indicate that their authorship is known). So, if you just take care of the look-and-feel issues and perhaps adopt one rule from these original versions you'll probably be fine.