I think the tables at the 2008 Worlds had the low-profile bearings in them. I seem to remember Dave Courington mentioning that they had to replace all of the bearings in all of the tables before the tournament.
And the problem was really not the bearings, but the bumpers that caused the problems. The bumbers arrived a little wider than spec. (or right at the top end of the spec) and the bearings were right at the top end of the spec. already. That combined to allow the ball to squirt through on a tight wall pass. And since they were getting ready to replace the bearing mold anyway, that was easier to change than to reject thousands(?) of bumpers.
But the new bearings (I think) were not ready for worlds 2008, so they "shaved" the old bearings down to the new spec. and installed them on the tables.
Ed G might have a little more info about this.