I broke one of my ROPs light assemblies (signal/brake) and went to the dealer to buy a new one, when on a whim I asked about the fancy rounded ones from the 3Rs and other large premium tractors. Turns out they were cheaper (something like 65 vs 85, but I don't remember exactly). I've always liked how those look so we measured to make sure it would fit and I bought a pair.
They are a direct bolt on replacement with the same wiring harness. Although the square ones have two black wires coming out of them, after a few inches they are spliced together (these have only one black wire). There is a "right" way and a fast way to install these. The right way is to remove the old wires and feed the new wires down through the ROPS and use the plugs to connect them. This is a nightmare on this tractor. I had to remove a bolt from the ROPS because the old wires were wound around it. This made the metal piece the ROPS was attached to shift position and I had to use a wooden pry bar (so no scratches) to force it back into position before I could put that bolt back. I then attached the old wires to the new ones and tried to pull them through. They wouldn't go. There was another bolt I could have removed, but at this point I gave up and cut and connected them near the mounting location. If you do it this way, it takes about 5 minutes install these.
They look great, work perfectly and don't cause any fault codes (like trying to replace the bulbs with LEDs did). I'm pretty sure these will work for any tractor that has these square light assemblies, including the 1 series.
For those who don't know what I'm talking about, this is the difference between the original lights (right image) and the new ones (left image):