BastyPutt
Yes, your Polish is a cockerel...
Yep, the white dot on a chicks head means that it is going to have barring.Actually 3 Midnight Marans and this one plus 2 barred rocks. My daughter kept the barred rocks. The others in this pic are Americana Easter Eggers. This is the questionable chick a few weeks ago. Notice the white spot on top of its head. It also had white under its tail feathers. I'm pretty sure my daughter's barred rocks both had the white dot on their heads as well. They are supposed to be girls.
A midnight majesty is going to be what is known as a "sex linked breed". This is when two specific breeds produce a chick that you can tell whether it is male or female when it is hatched. In this case, The males will have a white dot and will look significantly different than the females (pic attached) this allows the hatcheries to easily sort the chicks opposed to having to sex them and USUALLY gives the buyer peace of mind knowing they won't get rooster if he is unwanted.
However, because the midnight majesty Maran male chick very closely resembles the barred rock chick, at some point along the line, your rooster found its way into the barred rock bin and was mistaken for such. Because of the obvious difference between the male and female Maran, I would imagine this happened early on in at the hatchery OR the midnight Marans were being sold as a straight run at the farm store (which is unlikely)
The picture with 3 chicks are the Marans, with the cockerel on the right and Female on the left. And the other pic is a barred rock (unsexed) chick. You can see how closely they resemble each other.