Hrmm, my mistake. I had a Mercedes friend look at the car and he told me that it was built in October of 2004. I had thought he looked at the VIN to determine this. But oh well - the keyfob does say "05 CRSF" on it (and it's a clear one).
I had to change it to a local rental today, and the counter person looked up the car and was puzzled as I was at the age of the car. But then he said according to the computer, it had only entered the Hertz fleet in late September of last year.
Maybe the theories of Chrysler unloading it at significant loss are true....
That being said, it's a decent car (aside fromt he wiper and headlamp issue I mentioned earlier), and I would far favour it over a 'stang despite it being a two seater.
It's definitely a confused array of Chrysler emblems and Mercedes-Benz parts and switchgear.