Molasses is almost certainly gluten free. When I was diagnosed ten years ago, molasses was considered off-limits (or at least suspect) because of the food coloring it might contain.
Today, molasses is OK according to the Celiac Sprue Association’s Gluten Free Product Guide and does not appear on either the safe or the unsafe food lists published by Celiac.com. Reputable websites like About.com and Celiac Chics publish recipes that include molasses without any special notes about possible problems.
Please check out this recipe for “Roasted Molasses Sweet Potatoes”, produced by The Gluten Solutionand presented on You Tube.