"[6] In 1980 Margherita Guarducci, a leading epigraphist, published a book arguing that the inscription had been forged by Francesco Martinetti, an art dealer, and Helbig, who were known to have collaborated in shady dealings.

[8] Evidence in favor of the genuineness of the text came from a new Etruscan inscription of the Orientalizing period published by Massimo Poetto and Giulio Facchetti in 1999.

The inscription scratched on the body of an Etrusco-Corinthian aryballos shows a gentilicium, Numasiana, which provides confirmation of the genuineness of the name Numasioi on the Fibula Prenestina, often regarded as suspicious by the supporters of the theory that it was a forgery.

[3] In 2005, based on epigraphic and other arguments, linguist Markus Hartmann concluded that it is justified to assume the authenticity of the inscription as long as there is no compelling evidence for a forgery, and dated it with confidence to the seventh century BC.

[9] In 2011, new scientific evidence was presented by the research team of Edilberto Formigli and Daniela Ferro, whose optical, physical and chemical analyses allowed them to take into consideration smaller scrapes on the surface of the object than was possible in the 1980s.