Whether Moore is a true believer is not the issue. Although he ran as a Republican to get into office, if he runs for President on the Constitutional Party ticket and draws 10% of the people who voted for Bush in the last election to his party, as you claim and allows a Dem to win the presidency, count on Moore being as despised by the Republicans--just as Ross Perot is despised for helping Clinton into office in 1992.
However, if Moore wants to run on a third party ticket--and it seems as though it's what you're advocating--there's nothing anyone can do to stop him. In fact, with very little editing, his speeches could be converted to stump speeches. And with 10% of the vote, he could probably make it into the national debates.