Yes, the calipers are original. Since I bought the car (about 3 years ago) I have my mechanics flush my brake fluid annually. The previous owner had complete and regular dealer service done to the car as per the Mercedes owner's manual recommendations, including brake fluid flushes. Since I didn't remove the pistons, I didn't check the bore but the pistons were nice and shiny - perfectly clean.
Since it is cheap to change the brake fluid, I do it annually. I live in Ontario and my car is driven during the winter. It's pretty harsh with all the road salt - perhaps one reason the outer seals corroded so completely. I'm amazed the pistons were still in excellent condition.
2007 E550 4Matic - 61,000 Km - Iridium Silver, black leather, Sport package, Premium 2 package
2007 GL450 4Matic - 62,000 Km - Obsidian Black Metallic, black leather, all options
1998 E430 - sold
1989 300E - 333,000 Km - sold
1977 280E - sold
1971 250 - retired
"And a frign hat. They gave me a hat at the annual benefits meeting. I said. how does this benefit me. I dont have anything from the company.. So they gave me a hat." - TheDon