MAHLE Casting Numbers on Pistons: 80P24 E https://pbase.com/image/156437662 but I've heard these are not 100% exactly the same as the early 906 pistons. The early 906 pistons were spec at a higher compression (10.5:1).

The MAHLE cylinder barrels on the new batch of so called 906 pistons have a dramatically different casting https://pbase.com/9146gt/image/156437646 with thinner cooling fins, etc. I can spot an orignal early 906 cylinder https://pbase.com/9146gt/image/35129518 from the newer part from more than 50 feet away. Don't get me wrong, the newer parts are better using the latest technology, having said that, they're not a direct cosmetic replacment if one is interested in maintaining the original "vintage look'n'feel" of the 906 racing engine.