Those seem to be the same as the ones I've bought, part number 28244 is identical.
I've got the mud flaps fitted by the dealer before I've got the car, so I can't compare how much more dirt would I get without them. Plus the street where I live, as well as several others that I use to travel to/from work, recently got repaved with new asphalt. But from my previous experience, they do make a small but noticeable difference.