Big Chuck Says: “What’s Up With These License Plates?”

In going through a bunch of my Dad's old things I came upon several of these old 'license plates."  I vaguely remember them, maybe from the early 1960s.

But what are they?  Clearly they are not official license plates, but they obviously were meant to go on an automobile.  Also, there are no covered bridges in Sidney, Unadilla or Bainbridge!  Sure, maybe a hundred years ago, but not now.  Were these Chamber of Commerce fundraisers?  Were the three communities trying to band together in some sort of "branding unification?"  If they were sold, how much were they?  Were they a success?  Or a marketing failure?

I really have none of those answers.  Do you?