Read the full gun law. Get legally registered and check the new law, any Maine resident can carry. New York safe act screws most residents.
I would contact store my father carrys but its concealed. So unclear about open carry.
I'm not sure what store policies are. Maine law allows open carry, however you may want to contact the customer service desk before you arrive.
If you have a permit I would guess so, as long as your careful.
Thanks! Your answer is awaiting moderation.