First it is called a "planchet" not "planchette". A planchette is: "a small board supported on casters, typically heart-shaped and fitted with a vertical pencil, used for automatic writing and in seances" Second most of the time these are just commonly called "clips", and yes you do appear to have a genuine clip as the edge by the clip is slanted toward the clip and there appears to be a very slight blakesley effect on the opposite side of the clip. There are collectors that like to collect these types of errors, I am not one myself so I cannot say with any degree of certainty on a value, my WAG is about $50.