This can also be seen in early Palmers but it's not very common. It was a solid pin used to prevent the joint screw from turning. This one is pretty visible but when they are polished smooth, you really have to look.
Paradise and Rambo pinned the joints.
Good info, thanks. There is an interesting cue im looking at with a brass but plate, rectangle MOP butt inlay, carved handle into ebony titlist with points cut off by the joint, it a Frankenstein looking cue, makes me think of the outside the box style of Paradise but im far from an expert. Heres a few more pics,