 I don't know for sure, and if you do know, proceed; but I find it astounding that an Arian would not have been baptised if they entered the Catholic Church. The equivalents today converts to Catholicism from Mormonism or Jehovah's Witnesses are baptised, precisely because those religions don't believe in the Trinty, and therefore Catholics regard them as not truly baptized. Now if you have sources that the practice was different at that time of Clovis, go for it. Personally, I'd just be very surprised.