There's two different decorations on the pickups other than the plain versions.
The 80-1575 shoes a molded ALEMBIC in block letters. These are castings of the master which was engraved, so the word is deep in the polyurethane.
The gold version is a hot-stamped transfer of the Alembic script. These are on ABS plastic shells.
When did we change any of these things? I don't exactly know. It's not something we record, so going by the pictures in the Showcase threads will probably get you at least close to the times we did it. Of course, you can always custom order with any pickup decoration you want, even things we haven't thought of yet