Kinda a pain to figure out, but you can judge whether its intake or outtake by the way the blades are, or (in most cases) which side of the fan has a label on it. Most fans (or at least all the ones I've ever seen) put their label on the backside of the fan...the exhaust side. So if you look in the case towards the front, and you see the fan label, it should be intake. And on the back one, if you look in the case and to the back, you shouldn't see the label...or alternately if you look at the rear of the case from the outside and you can see the label, then yes, the rear is exhausting the hot air.
The true way is to check what direction the fans spin and then look at the angle of the blades, but it's harder to explain that one. 😉 Just look for the labels...
Since 99% of cases are front-intake and rear-exhaust and most of the manufacturers have been around for awhile, I'm sure the system was shipped with the fans facing the correct way, but it never hurts to look. 🙂
You should be able to remove the side duct and mount an additional 80mm fan if you want to. You could alternately probably put one at the bottom (maybe with screws, but you might be better off using cable ties.