What plane is this?

This morning I watched a rerun of an episode of Route 66 that had an interesting amphibian aircraft featured and I'm wondering what it was and if anyone has done a flight sim model of it. It was similar to a Grumman goose or widgeon except the main wing was in a gull like configuration and the twin props faced aft as opposed to forwards and the engines appeared to be reciprocating as opposed to radials. The registry number was N400024 if that helps any. Since the episode was filmed in 1963, the plane had to be a 1950's or earlier model. Anyone out there have some info on what manufacturer and model aircraft it was?