Most, if not all, of the earlier EMF revolvers were made by Uberti, with the exception of their cap and ball revolvers (I bought a pair of '58 Remington cap and ball revolvers around 7 years ago from EMF. They're Piettas. I still shoot them). I think Uberti stopped supplying EMF when Uberti was bought by Beretta.That's about the time when EMF started selling their Great Western II revolvers and sourced them from Pietta.
By the way, the GWII Alchemista is named for Alessandro Pietta, who's SASS alias is ...... Alchemista. I met him at End of Trail this year. Really nice guy, very friendly.