False.You should have 2 cabin filters like we do the the W210. One is activated charcoal (expensive) but I don't remember the proper term for the other.
You have ONE Cabin Air Filter. This is the same as the Dust Filter. You can buy either a regular version, or an Activated Charcoal. The Charcoal version removes dust AND odors, while the Standard version just removes dust. In terms of price, if you buy them online they are usually about the same price. In Fact, the Charcoal version is sometimes cheaper...NOT EXPENSIVE at all.... like maybe $20. There is a post in the DIY section to replace this filter (under the passenger side dashboard). Ive done it twice in the past 2-3 years, and its very simple. Dont dare pay the dealer to do this for you!!!