Achim, I don't think I have ever seen a 126 in the US with steel wheels. They all have Bundt alloys or the 15 inch ,15 hole alloys.
Since last year I see aftermarket 15inch bundts for sale at about $150 US each, a modern look on a 113.
What years did the factory offer Bundt wheels on 280 SLs as an option and was there ever an option for 15 inch bundt wheels back then ?
I know that 15 inch bundts were an option on 107s.
jz