[HO LEMANS]

Ok I am in the slow process of restoring my 69 Lemans and I was looking at the vent control doors and the mice have decimated the rubber around the doors so I found a whole new housing at the local salvage yard (also a 69 Lemans) now my question is this .... why does the one I picked up have 2 vacuum pods and 2 small doors (I do understand that each pod runs each door) instead of one pod and 1 large door like my original ..... was this some sort of option I am unaware of or ???