Shifter Question

Hello WJ community,

I have a CJ3A and been driving great and suddenly the other day the shifter just locked up in 2nd high. We managed to get it home and I pulled the shifter out to inspect it. It was still jammed after I pulled it off, so it was definitely the shifter.

I took it apart an cleaned it up real good and noticed the poppet balls were worn and rusty - so I have ordered new balls and springs...then I noticed when taking the shift rails in and out that there was another part that may have been part of the problem - the "interlock plunger" which is small pin-looking piece of metal that is about the size of a 9mm bullet lead that bridges across the two rail holes and "locks" the rails when positioned in certain ways.

After getting the plunger out (drilling the cap off and fishing it out with a combination of liquid wrench, magnets and heavy duty wire) I noticed one side was rounded like the tip of a bullet and the other was worn and flat. When looking online I noticed that both sides are supposed to look rounded. So, my question is....will the shifter work without the interlocking plunger? I really can't understand exactly what it does.