The Duncan JB has been exactly the same from day one. Unoriented, roughcast magnets have never been used in any Duncan pickup in their history.
This is mostly true. Rough cast and unoriented are two different things. All Alnico humbucker magnets are sand cast, the difference is that ground magnets are sand cast oversized, then ground down to a precise dimension, with a smooth, flat, polished surface. When someone says "rough cast" (which is sort of a made up term) they mean that the sand casting is attempting to make the magnet the exact size, but of course leaves a rough surface. Even what we'd call a sand cast magnet still has the important dimension (the one along the pole pieces) ground to precision. You wouldn't really want that surface to be granular.
Old JB's did
not have unoriented magnets, but they did have what forumites would call "sand cast" or "rough cast" magnets, where the sides facing the strings and the guitar body are rough. Even those surfaces can be passed through a grinder to knock off high spots. Occasionally you'll see magnets like that with a few shiny spots across the top surface where the grinder hit. These magnets are used in the Antiquity JB/Jazz. The result is less predictable. When making a production pickup like the JB, I would say it's "better" to use the ground magnets, for the ultimate in precision and repeatability. But for the Antiquity and 35th Anniversary commemorative, we went with the original.
These magnet differences are a very small. By answer to this post I am not agreeing with anything said by anyone about JB's, EVH, AT-1, etc. Just clarifying the magnet talk.