That is the composite, one of my hunting buddies has one of those. It uses some carbon and plastic parts in place of aluminum to reduce weight by a couple ounces. It was phased out because it was “cheapened” and still at the same price point as the others. The sales on them were way down so they cut them out and went full black synthetic made the same way as the camo ones.
My buddy always says he wishes he had the 3.5″ model when we are goose hunting, but for ducks its a pretty nice gun. He bought it used so that is why he got 3″ instead of 3.5″. If you have not shot it yet, consider trading it in for a 3.5″ model. Worth the extra few bucks to upgrade. I have shot his gun a few times at the range and once in the field, it is pretty nice. Not as nice as my fathers duck blind camo 3.5″ SX3, but it is still pretty nice.