I think my Eleanor's eggs are darker than that. She occasionally has those tiny spots on her eggs, but so does my Welsummer. She's a pretty regular producer, and the eggs are on the large size.
Now that she's a little older, does your girl have feathering on her legs? Eleanor has just a bit...
The good news: I have one of Hoover's Midnight Majesty Marans. The bad news: I am technologically challenged and don't post photos. Yet.
However, if you put up photos, I will be happy to offer a written comparison :D of my girl's appearance and eggs. Eleanor's are the darkest among my layers...