What markings would there be on the group buy 6.5mm mold from long ago. The group buy that I think was spear headed by member oldfeller maybe? Member 45.2.1 might have also been involved in the dimensions, as I recall.
I just bid on a mold on evilbay and was told by the seller that it was an old Lee group buy mold. He could not provide dimensions, it was unused.