Okay, first of all, the SD9 or SD40 didn't exist in 1994, that would be the SW9F and SW40F. (The SD9 and SD40 weren't released until 2012.)
Second, to the best of my knowledge, there's no such thing as a Performance Center of any entry in the Sigma Series, so if such a thing does exist, then I would very much like to see it and would greatly appreciate it if you would be so kind as to upload some pics of these Performance Center Sigmas.
The closest thing to Performance Center Sigmas that I'm aware of are a few limited runs of special models like the SW9P with a Ported Slide/Barrel, but that wasn't a Performance Center model, the P stood for Ported.