I thought that was what the spoiler/vent covers were for
Actually when I measured the height of my 2010 30SK I hooked it to my TV, put a laser level on top of the AC and then held a tape measure where the laser would hit it. I'd have to check again but I believe mine was 11' 10 1/2".
I have a sticker on my sun visor that has the height of the trailer and the height of the truck without the trailer. I have my GPS bridge warning set to 12' 3".