$32. bucks for a re-pop in metal ....if it were me I would get a new one ....original stuff is nice but when you consider pitting and fading on top of how people put their grimy mitts on it over the years and probably picked their nose and then shifter gears J/K........new ones are johnny on the spot and with a warranty.
Of course you know shipping will be a fast closing door and slap on your behind.
http://www.pgclassic.com/367-mbut-mopar-1966-68-a-b-body-shifter-knob-metal-button/