I HIGHLY doubt they off anything but THEIR pin.
You realize any shaft made for "their pin" fits a standard 5/16 14 right? The joint diameter Pechauer uses is a hair larger (.845 or .850 IIRC), but not enough to notice.
In fact, to convert a regular 5/16 14 shaft inserted shaft to fit on a Pechauer, only requires boring the insert to the proper depth/diameter and it will fit too.