Why look at the cluster when you can just look at the HUD. You can customize it so it shows road name, speed and limit, or just 1 or 2 of them. If you've got a Laramie I assume you have this feature. Maybe not, you know what they say about assuming.
Anyway, have it or not, it's not 100% accurate anyway. It's usually pretty good, but I've found that when it's wrong it typically says it's a 25 zone. This becomes quite obvious when my speed alert (I have it set at 8 over) tells me the speed limit is 25 in an area I know it is not.
Posted speed display is nice, but I watch the signs. I could probably just set my HUD for speed and road name, but it doesn't hurt to have the limit displayed too, since it's right most of the time.