ok more 'getting to know you' questions about my new '83 gti cab!

Are these the correct wheels for the car? They are running 185/60 R13's all round. The speedo seems to be registering a bit fast, and a 6 mile distance on the motorway got measured as over 7 on my trip.
Secondly, WTF does the dial above the headlight switch do?? Mine does nothing!
that'll do till I think of more!! Many thanks!