They will fit as they use the same mirrors & covers, the mounts are same from all I can work out after looking at some facelift a3's today, Audi will always tell you another chassis's parts wont fit another as a rule even if we know different.
The covers & mirror glass are exactly identical size/shape, I have a set of covers at the moment which I'm looking for the rest.
I have to agree with NHN, they will say they wont fit because thats what the computer says! The computer is worng more often than not. My brother used to work in parts and he said he was suprised on a daily basis which VAG parts were compatible! They also have different part numbers between manufacturers but are exactly the same part.
You wont be suprised to know that a huge amount of Audi parts are fitted to VW/Skoda/SEAT under different numbers but are identical and even come in the same box! If I know something might be compatible i always ring the SEAT/Skoda dealers first as they are usually cheaper.
Excuse me while I go out & clean my A4 alum covers & mirror glass on my A3.
Point made I think!!!!
Again I repeat, Audi will not as a course tell you a part from a certain chassis fits another chassis, its a standing joke with me & my parts guy that I pretty much deal with daily, different part numbers on my mirror glass & covers but fit 100% to my A3
Everyone learns in time as I did & yes amazing how the price is different huh