You can install the 69-91 style cab markers on a regular top.
GM totally screwed up the marker lights on the newer trucks when they did that weird thing with bunching the three center lamps up. Cab marker lamps are a truck tradition that doesn't need messing with. You see five lights on top of a vehicle, one at each end and three in the center, and it lets you know a larger heavier vehicle is coming at you. I always knocked Ford for screwing it up with insisting on placing all five evenly across the top. Then, when GM made the center three one unit my Ford buddies were the ones saying "What were they thinking?"
It's just like the big mirrors that are needed on a truck. Some let the mirrors bother them. I like them because they belong. They serve a purpose, just like a truck. We see them because they have to be there, so they don't bother me. In fact, I embrace them. "They are a truck thing. If I have to explain you wouldn't understand"
