I have a boat who's previous owner applied Awlgrip. The starboard side is mint, but the port side has the look like the photo you posted. It's never been touched by wax or anything and has lived an easy life in freshwater. In fact, the boat has only been in the water for 4-6 weeks in the past two seasons.
The marks are like streaks. My only guess is that the petrol deckplate is on that side, but the marks aren't by the deck drain, farther forward.