Awlgrip is pretty tough as paint finishes go but no where near as scuff resistant or dueable as gelcoat. Awlgrip is actually quite soft for the first year or so that it is on a boat. It gradually gets harder with time, that said it is easily marred by prolonged scuffing such as might occur with a fender. Most people with awlgripped hulls try to avoid situations where fendering is necessary, use terry cloth protectors on their fenders and frequently clean the terry cloth after useage.
Now for the bad news, while there is a slight chance than the dullness is simply rubber from the fender ground into the surface of the awlgrip, (in which case a mild non-abrassive detergent should wash the dullness away) it is more likely that you have abraded the surface of the awlgrip. While the color goes all the way through the material, awlgrip actually cures into multiple layers each with their own unique characteristics. The upper most layer is the hardest, most UV resistant portion of the paint layer and creates most of the sheen and moisture resistance. When that layer is gone there life of the Awlgrip job is greatly shortened. Using abrasive waxes or polishing compounds may temporarily return the shine to the damaged areas but they also shorten the lifespan of the finish by removing some of the surface layer.
Sorry to bring the bad news.