All my 2nd variant pistols with the normal blade front sight have a pin with knurling along one third of its length and have a pointed tip. It certainly seems that the assumption of a 3rd manufacturer's variant is a valid one, but it would be nice to find other examples.

By way of a bump for Jimmie's original enquiry: If anyone has a plastic grip Diana/Mllbro Model 2 pistol lurking in a cupboard somewhere, could you dig it out and let us know if its a 1st or 2nd version, and what type of markings it has? Many thanks.