Not 100 percent sure, but I've seen some of these weird bricks before and I think they old (wouldnt bet lunch on it, though), but maybe they were juat a weird batch. I also believe they are Akro and not MFC. They are usually in the 5/8's range, with 11/16 being the biggest I've seen. The guy that has the USA Display website, who also sells Mibs, has quite a few of these (if I had any credence before, I probably just lost it after mentioning that guy, lol)