wheel swap

Hi All Is there anyway I can find out what the original wheels that were fitted to my 1997 SL320 would have been? It has genuine 16" Mercedes wheels on it at present but I don't think they are original - the spare doesn't match! As I want to change the tyres - it has odd ones on the rear...

Just had my summer tyres put back on and for the first time Mercedes Aberdeen charged me £62 for the privilege. Up until now I had paid £60 per annum for storage and the wheels were swapped twice a year. This was a good deal. At £184 this is not quite so good. Just wondering what other...