If they are like the Williams boards, the hangers are a drive in with a spiral, like the old spiral nails. They have a boss at the top of the spiral, which I believe is a register so a tool could be used to drive the "nail" part into the board without touching (or damaging) the hanger part.
This type of hanger is not designed to be removed, and often takes a big chunk of the board with it when it is removed. Being able to twist it while removing may help reduce or eliminate the damage to the board.
. And to answer your question, no you can’t remove the prongs without seriously damaging them. I would recommend you find some 1”x1” wood at your local box store and cut it into 4” long strips( longer than the prongs). Flip the boards face in on themselves . Then you can use the already drilled corner holes to run screws threw and into the wood spacers. It makes the boards more sturdy for shipping and keeps them protected. It’s almost like I have purchased a few tool boards mail order before 
