I would like to see a photo...

By “same shot” I mean just that.  Same composition, taken at the same time.

In my several posts to this thread I’ve tried to put forward my view that your original question, as posed, doesn’t really have an answer.  I mean, for any given transaction we do know what was purchased (or not purchased), but there’s no way to know whether the purchase decision would have been different had your imaginary second print been present and available for comparison and sale.  We don’t even know whether there would have been a visible difference, much less the value the potential buyer would place on such a difference.