You will see that it's the angle of Bob's images that make it appear to be just a single door by an image at this website, while it is a double door..

Buffalo South Entrance Lighthouse

Also in the historical image you can see that the light is on the end of a breakwater at the entrance to a harbor, horn pointed out towards the lake. There is some good information on this page also..

It appears to be for sale..

Sale information web page

Image of doors