Possible 1964 Clad-Struck Roosevelt Dime

There is a posting in another venue (posting exact web address not allowed here) that shows (photos) a 1.6 and a 1.8 gram presumed thin planchet 1964 Roosevelt dimes. Both have significant appearance alterations involving details around the rim. Notable both have nearly invisible "4" part of the date stamp 1964, as does our sample. Rough thickness to weight ratios of our sample and our other examples seem to be consistent with high silver content. Until further testing (XRF and specific gravity) can be accomplished, thin planchet is looking like a plausible explanation.

I also found a 1964 dime no mint mark two weeks ago and it weighs 2.25 grams, no sign of cladding and the dropped sounds is like a silver. I was hoping that this underweight coins may be considered another type of variety.