The lack of a reliable specimen or photograph thereof makes it impossible to verify the authenticity of any specimen found today. A rich variety of possible counterfeit methods are possible, from modifying the date of a different date 10 Centavo to casts and doubtless many other means imaginable only to counterfeiters. Either all or nearly all known specimens known today show characteristics of one or another of these techniques. It is not known if even any of the doubted specimens existing today would not conform to some one or another of the known counterfeiting techniques as many of what samples known, when shared at all (which is rare), are not shared with experts sufficiently familiar with, for example, the other dates that could be used.
In the absence of a certainly authentic sample, there is no way to verify the authenticity of any sample actually found. In short, even were some actual specimen to be found, we could not be certain as we have no criteria against which to measure and compare it.