Nothing to say, really, they made two versions. I slightly prefer the curved button layout, but unfortunately, nobody has reproduced that CPO. If you want to swap the CPO, you'll have to track down a control panel with the correct button layout.
You'll want to make sure you get the correct kind for your machine, the 4-slot uprights have a memory card slot and shelf for the card reader to mount on. The 2-slot has the memory card reader on the PCB, and the 1-slot has no reader, so the CP doesn't have that part on those cabs. I've also seen 4-slot CPs factory converted to 1/2, they have plated welded over the slot the card would go through.