+1. The "brown" in brown sugar is molasses. Used to be that brown sugar was less-refined white table sugar, but some decades ago - IIRC, around WWII - it was found to be easier to add back a measured amount of molasses than stop the refining process mid-stream.
The flavor and color contribution of the molasses in brown sugar, regardless of color, will be slight. It depends on the rest of your recipe; for example, if you're using nothing else but pale extract, dark brown sugar will have some impact. Otherwise, it's just additional fermentables. If you post the rest of the recipe, I'll be better-positioned to actually give you useful advice.
Bob