I should have mentioned the interior of the LID does have the smooth, sand-colored enamel. It's the interior of the POT that appears to be uncoated cast iron.

My two round LC ovens (purchased within the past two-three years) are Satin Black with the black interiors. Satin Black is a discontinued color BTW.

According to LC, they are coated inside and out with the same black (non-shiny) enamel. I purposely chose that color because I not only liked the satiny black itself, but I liked the idea of the black interior. I figured the lighter-colored enamel would eventually show stains/discoloration. I usually add a sprinkle of BKF (Barkeeper's Friend) when I'm cleaning them, and they look like brand new.

Sounds like your French oven has developed a polymerized oil/carbon seasoning like a regular cast iron pan. Yes, enameled Le Creuset cast iron pieces can be seasoned (intentionally or unintentionally). I would be willing to bet that underneath that coating lies a sand colored enamel surface.

Dan