According to this www.wheelfitment.eu/car/Audi/ , the Audi RS4 (and A4 and S4) should all be 5x112. So if these wheels are genuinely from an RS4 they should be 5x112. They might be 5x100 copies of the audi wheels perhaps? or the seller has just got it wrong. Might be best to ask what they were last fitted to, in order to be sure 
