Quoted from TractorDoc:(I pulled the plastics to obtain an accurate post count for ordering purposes.)
Be aware that the reproduction blue Stern posts are NOT the same colour as the original ones you have. You would be fine if you are replacing all of them, but if you mix-and-match, it's quite noticeable and unacceptable . I ended up choosing to keep the somewhat worn originals, and hunted pinball scrap-piles for a while to get enough to complete the game.