The relative sizes of the coverage angle on either side of the lens depends on the type of lens. On a conventional semi-symmetric prime focus lens (tessar, biotar, planar etc) the angular lens coverage should be the same on either side of the lens. On a retrofocus type wide angle lens the coverage angle at the back (what is normally the film side) will be smaller than that at the front. For a telephoto (reversed retrofocus) lens it should be the other way round.
Reversing a lens and using it at infinite conjugates (objects a long way off) may not work that well as the lens has been optimised to work the other way round. This will degrade the performance but I don't know how badly (will depend on the lens).
Your assumption that the front focal point will be the focal length away from the front of the lens may bot be correct. The front focal point will be the focal length away from the front principal plane of the lens and the back focal point will be the focal length away from the back principal plane. Both principla planes will usually be somewhere inside the lens and separated by a distance depandant on the lens. With standard lenses (most semi symmetric 50mm designes) both principal points tend to be closer to the back of the lens. This would mean that reversing the lens would reduce the distance you have rather than increase it and make it impossible to focus to infinity. This is why remerse mounting a lens makes it work as a macro lens, it has the effect of adding extension tubes.
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