To put the little rubber thing on the inner fender I would have to poke a couple of holes in the car. I'm not going to do that, especially when I can avoid it by having a battery with the posts reversed from how they are supposed to be on the 'correct' battery.
And yes, the terminals are supposed to be to the back like you thought. With the correct battery, that puts the positive over next to the inner fender. If you look at the battery top on my car, the post that has the negative cable says + and the one with the positive cable says - .