You're right about the Langematik. Lange didn't make an "official" blue-dial variant. My watch was born as a black-dial 301.027. Then, in the late 1990s, the original purchaser (who was well known to pre-Richemont Lange at the time) learned that a blue prototype dial existed, and Lange agreed to put that dial on his watch. I was fortunate to find this! The original purchaser actually wanted to auction it, but he said the auction houses he contacted were taking too long to authenticate it (because of the blue dial they had never seen before), so he went ahead and sold it (to me) on his own. It came with nice provenance -- some letters/notes between him and the Lange factory from the late 1990s.