I did an image search with duckduckgo (something like "Mac OS X time and date widget") and scrolled until I saw what seemed to be pretty close to the OP's pixelated example. You know what's odd though? I just tried doing the same thing just now and I don't see it in the results. The stars must have aligned that other day, today not so much...
(Even though I am old enough to have used vintage macs when they were new, I had switched to using Windows even before OS X was released so don't personally remember the widget itself.)