You are right about the twins' real names, with Mary-Kate seeming rather 50s and Ashley being on-trend. Their younger sister is Elizabeth, so it would actually seem like Ashley is the odd one out of the sisters (with a name more trendy than classic).
I also looked up Mary-Kate, to see if that was actually a nickname for Mary Katherine (nope, it's her legal name), and... I had no idea that former French president Nicolas Sarkozy is her brother-in-law. Wow.
And I'm glad you found the name of the show! On the show, Mary-Kate played Riley and Ashley played Chloe. But in their movie "Winning London" (which I loved as a kid - they're in a United Nations type competition), Mary-Kate played Chloe and Ashley played Riley!
Please rate my personal name lists:
www.behindthename.com/pnl/69381www.behindthename.com/pnl/69381/109399www.behindthename.com/pnl/69381/91835http://greens-end.myminicity.com