Flip Top restore help please

Hi, I tried that, I found it easier to buy a repo for the $100 bucks or so...
But, the roll pin needs to be knocked out to separate the "cap" part, then (Im not sure is this is possible) you need to somehow remove the "plunger" part ...I think that part is pressed together? It looked to me it would be destroyed trying to remove the plunger? Maybe someone else has a thought on this.