Brain Teaser Question/Backwards Mono-Wiper

[Boston Benz]

I recently bought a 1995 E320 sedan from a 90 year old man. When I looked at the car I noticed the mono-wiper was in the park position but on the wrong side of the windshield (passenger side-as if the car just came from Ireland or England). I asked him why that was, and he said that he had the wiper motor replaced last year. He also noticed it wasn't right and the mechanic told him he "installed the motor backwards" - whatever the hell that means...

Obviously this previous owner didn't take any action to have them fix it. I am now replacing the pollen filters and want to park the mechanism/wiper over on the driver's side. My quandary is how to get it over to the other side. The wiper motor is in place correctly, i.e. not "backwards or upside-down - it can only go in one way. The entire mechanism (I'm guessing) needs to be "moved". I don't know if it's as simple as undoing the nut on the motor spindle, lifting the mechanism up and indexing it over to the opposite side - is it that easy? I'm having a hard time trying to visualize how that would work, and the movement of the mechanism at the firewall. Any help would be appreciated...