pics would help a lot. If it's a stock WGP cocking rod then it had wrench flats on the end of it. Most cocking rods have a set screw that hold the end in black that is located in the back of it or it goes in from the side.
some of the old cockers have a hold drilled into the side of the lower tube that get you access to a set screw that holds the cocking rod in place
if all else fails, put it in a video with either a thick leather glove or a piece of rubber so you dont mare up the end.