They say it on their page. Mastertrader777 is the lead developer. But he's admitted that he doesn't code before. He outsources development work.
This page is kind of embarrassing with all of the bad grammar and such.
That's the old page, hasn't been updated since version 1 (stillborn). I wouldn't assume Mastertrader777 is still involved unless he decides to confirm himself. Not sure why he would commit source code under the name of "Kieth Harville".
Why don't we ask him in the Mastertrader thread? If he says he is not, then Keith definitely lied.
But I'm telling you, he is. He and BitStoneDev have identical vocabularies / writing styles.