MM has an error guarantee, get with them and send them pics and they will reimburse for any birds that went over the limit. So if they sent you say 2 extras then they will refund you for 2 birds.
Definitely a rooster. I can tell because of the long, pointed saddle (lower back) and sickle (tail) feathers, as well as the light coloring. Dominique hens are much darker in color.