Hey Six. The coolant that the 2012 RT had in it when delivered new was the green stuff, not the orange stuff. Apparently then, somebody did some maintenance along the way. So, if you are going to completely drain and refill, if it was me, I'd put the green back in it. What's the difference? Well, it's my understanding that the 998 Rotax still had some steel components in the coolant system, such as the water pump impeller. Maybe that's why BRP went with the green for that engine. Orange coolant is more appropriate for coolant systems that are completely aluminum and nylon.
Whatever you decide to do, when you drain the system, do NOT remove the drain plug on the side of the radiator. Much more often than not, it is so bound on there, that the solder joint will crack and you'll have a leak. Instead, remove the lower radiator hose. And if you decide to go back to green coolant, it would be wise to give it a flush first, to get the old stuff out of there. Just don't mix the two.
Any jug of the green stuff you find at Autozone, etc, is fine. Standard 50-50 mix.