Same dies as the apparently authentic specimen in
Paris,
Gnecchi pl. 98.4, previously in the
Vatican, acquired in the 18th cent from the
collection of Cardinal Albani.
The
Paris piece is very similar and might be the original from which the casts were taken. This may be an old
cast, produced in the 17th or earlier 18th cent.: for a similar specimen (or could be the same spec. as the one or two that you illustrate above) was already in
Basel 1, 1934, lot 1473, a
collection which
had been formed ca. 1850-1875 if I recall correctly.