Oh, I can't wait till I get my eggs that are as dark as those!
Those BCM eggs look to be bare minimum to qualify for a Marans. They must be at least a #4 on the Marans egg color chart. Those are a 4 at most. Here are some that my hens laid that are a #5-6, that row of 6 eggs, and a couple are only 4 in front of them. You can see the difference. And @moms3cuties there's my Ameraucana eggs

Oh, and this photo was taken in the shade, so no sun glare. See the photo following to see what the sun does to the color of the Ameraucana eggs! The Marans eggs still look nice, shade or sun!
In bright sun: