I grew up (1944-57) in Union Beach, New Jersey on the Raritan Bay. Adjacent to Union Beach is the town of Keyport. There was a cluster of factory buildings in Keyport that called Airomarine. In my time it was a variety of manufacturing operations. There was a railroad spur to it. This aircraft may have been built there. Here are some links I Googled:
http://www.aerofiles.com/_aeromar.html
http://en.wikipedia.org/wiki/Aeromarine_40
Harry