Finally found the area I think you are referencing - with a magnifying glass and a flashlight. Inner surface (car side) of the lower border of the exterior lens. Light needs to be angled just right to see it, but yes, looks like a mold mark of some type. Really keen eyes in Oz! I would never have noticed it until you pointed it out, but I suspect there are myriad bits and pieces of flotsam and jetsam all over the car if I took my Sherlock Holmes lens and a 1000w lamp and looked. Sometimes you just don't want to see sausage made!