If you are meaning these. http://www2.mercedes-benz.co.uk/con...e/after_sales/interactive_manual.html#mainnav
then the answer is the interactive manuals are a relatively new development by MB. The only manuals AVAILABLE for older models "pre-internet" were the printed owners manuals which came with the car. There was a website that offered them but I don't think its online now. You would be able to order one from any MB dealer I think.
yes older manuals are available from dealers and reasonably priced too,
however they only run off prints every now and then so you may get one quick or have to wait a while.
Found another source of online older owners manuals here. They are for the older S CLASS models only I think. http://bayhas.com:8080/w140manu/
they are not interactive but copies of the printed ones.