Hey there.... I'll start by telling you that I am NOT an expert.. You're question had me curious, so I started looking things up.. According to any diagrams I can find, and they aren't very clear, it looks like there is just a hose connecting the 2 thermostat housings together. I can only imagine that as a possibility if the idea was to open both thermostats if one side opens.. (Un-even head temps..)
Again... NOT an expert, more of a curious bystander and looking to learn myself..
I know others will know for sure, but just a thought to start with.
Also, if I'm not mistaken, I believe that model number you gave indicates a counter-rotation model..
Not sure if it's just the gear-case, but it would seem you'll need to keep an eye out for that tidbit.
Are you getting parts for standard rotation, or counter-rotation...
That's a new one on me, so I don't have any more info on that...
Again, Others will know for sure....
Going to follow along and maybe learn a thing or 2 if you don't mind! LOL