I wonder about retrofitting the park/emergency brake for a '17 and earlier 800 to one of these E brake-less models. I am lucky enough to have such model and I was delighted to find the E brake lever actuates a disk brake on the rear driveline. This is a manually operated and entirely independent brake to the machine's service brakes. The service brakes could fail completely and you still have an operating brake on the rear, and if you are in 4wd, a brake working on all 4. This was an elegant system and why CFM discarded it for an E brake that just consisted of another way to engage the service brake, I can't imagine, let alone the later still baffling decision to eliminate a park/emergency brake altogether!
But I'd think the parts to install a pre '18 E disk brake should be a bolt-o,n I'd think.