Originally Posted by Clemson88

I reckoned this to be due to there being many times more 123s than 126s.

It is my understanding that the dealers have no part in the production of keys and ignition cylinders. They check an owner's credentials and transfer the products. My guess is that if one dealer can get something then it's probably available to all the other dealers too.

It's strange that they'd discontinue keying for a w126 when the cylinders are most likely identical to the 126 save for the keying.