Wow, I guess I wasn't looking hard enough... www.parts.com has the Mercedes and Chrysler parts, but what a price difference! They are a hair cheaper than the Mercedes parts site. $26.40 each. I too would like to know if they are the same part...

Link to Inner Fender Liners on parts.com

Until then, I'll halt my project. I have the patterns already, so if I need to, I'll make them anyway.