In the state of Missouri is a trustee's deed automatically a warrantee deed?

I wouldn't think so, but you really haven't provided enough information about your question. See: Trustee's Deed Law & Legal Definition (http://definitions.uslegal.com/t/trustees-deed/)
And: Missouri Foreclosure Laws - Information and laws for purchasing foreclosures in Missouri (http://www.foreclosureuniversity.com/studycenter/foreclosurelaws/missouri.php)