Be aware that those are merely wipers for the sides & top, not the actual seals. Mostly they brush off debris and water so that it doesn't get dragged into the RV, though they do help channel water away from the real seals. Theactual seals are the D-shaped rubber on the inner and outer flanges that ress against the sidewalls.
It doesn't make a whole lot of difference if the wipers flip over or not, though it is preferred that they do. As lynnmor says, they rely on friction to flip them as the slide moves. If you like, you can put a strip of non-skid tape on the side of the slide to improve friction.
Or you could leave the 303 off. Despite all the internet chatter, the wipers will probably last just fine as long as the sides of the rv are kept reasonably clean.
