I'm sure with enough time and resources you could get anything to fit. But the fact that Rally Armor took the effort to make a Forester specific version leads me to believe that they are not going to be compatible. At least not without a good bit of modification to the flap or your car. What's the price you found? If it's REALLY good I you might want to buy them and try to sell them for more and apply the profits to a proper Forester set.
There is a seller on her with a RA UR Forester set for $100.