They are genuine Audi parts. They are part of the votex kit which was an optional upgrade just before the s-line model was released.
They do actually look quite decent when fitted, search my threads and although I had a sportback, you can see the complete votex kit.
Asad, yes you have done the right thing by taking the two strips off, otherwise the skirts will not fit in place. A bit fiddly but they will go, masking tape to hold things in place, and I would give at least 48hrs for the glue to set of properly especially in this weather.