Some handles such as the 6 pin are two separate slabs which enclose the full tang. I have two original 19th century knives that only have 5 pins, but they are identical to the 6 pin style.
19th century butcher knives.
Some blades only had a very short tang which was inserted into a sawn slot handle and secured with 3 pins.
This lower one I use as a hunting knife. When I made a handle for it I drilled through handle and tang and inserted one brass pin to help secure the blade.
Found at an Iroquois site.