Yup, he did have a permit.  He had also been smoking marijuana, and there was marijuana found in his car. 

Per federal law and Minnesota law, users of illegal substances (which includes marijuana) are prohibited from possessing firearms.  So not only was his carry permit voided by his partaking of marijuana, he was not legally allowed to posses the firearm at all.

But of course, anti-gunners aren't particularly knowledgeable about firearm laws, so they love to mindlessly parrot the narrative the NRA is racist for not rushing to the defense of Castille.