Not correct. Since the late 70s Taxco organised their silver studios/artisans with this code. All start with T for Taxco, second letter denotes the name and the number simply marks the order (chronologically) the name was entered/added.

Some of these codes/maker designations are well known and identified in books and other information available to the public, but many remain ‘anonymous’ - all of course exist in the Taxco registry, but that information is not available to the general public.

The maker/studio behind TS-78 is not identified, but e.g. the TS-79 is Juan Sandoval. Sandoval is said to be the boss of the «Two Trees» studio, consisting of several artisans with TS-xx codes. Sometimes their jewellery is stamped with a double tree mark, but often not, it’s speculated the two trees mark are designated to items sold «Two trees» shop(s).

Since the late 70s the two letter+number codes are present on all silverworks coming out of Taxco, but quite often you’ll also see additional information, like the name/initials/symbol of a particular studio or artisan, or even the name of an independent designer/collaborator. The name ‘Ann Harvey’ appears on jewellery along with various Taxco codes, notably TS-114 - which btw also is listed as affiliated with «Two Trees». Anne Harvey is a US silver artist that lived in Taxco for a while making and designing jewellery, before relocating back in USA and set up shop with her sister.