It's purely conjecture from my part, but I would say no. The Gazetteer information about their beliefs shows a warped version of Krynnish religious beliefs. This suggests to me that the original Sithican's either had their memories warped by the Dark powers at the time of their arrival, or, more likely, the original Sithicans are creations of the Dark powers themselves with the false history implanted in their minds from the beginning. Either way, a sithican priest of a krynnish god would most likely be rejected by his community.