That seems pretty hot. But I don't think there's anything really wrong with it. Probably don't wanna throw any hamburgers on there at that temp
Remember when new a grill will always run very hot. Because there is carbon buildup inside it so the metal surfaces will reflect much more heat and the thermometer will show it. After a number of uses you will not see those high temps anymore as the carbon will allow the grill to soak on that heat. No worry you're golden
You could always do what I used to do to get rid of the blue on my motorcycle pipes. Get a tube of simichrome and a rag after they cool and polish them up real nice. My fingers ache just thinking about all that polishing I used to do. Between the alloy wheels, the spokes, the pipes what have you, on my Guzzi the rocker covers it's a wonder I ever had time to get in the wind LOL
Yah, if said you were actually going to "polish up" those flavo bars, I would have had myself a good laugh at my keyboard.