It should be opening on the way up and closing on the way down. Also you can see the wear on the side that's been used.
Or are you referring to the the orientation of the housing itself? If so the carb opening goes up.
Oh ok. The slot with OPS stamped next to it is the one to use. If you ever question it just refer to what I said above about when the window should open and close.I'm only reffering to the rotating part. It's my first time taking apart and engine and i did not pay attention to that part.