Quoted from Joydivision:Your clear plastics are broken where the captive ball sits (you probably already know) which is a very common problem with Fireballs. The 2 posts in front are not original & have been added because of this.
However, you can buy replacement clear plastics from the Pinball Rescue from the link below is you want to restore the set up to original.
Pinball Rescue are closing for good on June 7, so you will need to order now if you happen to want them! I'm pretty sure you can't get them anywhere else.
http://www.pinballrescue.net/Plastics_Fireball.html
Thanks much for the heads-up!
For now, I'll keep it like it is. Blasphemy, I know. But the 2 posts installed on mine look like they will hold up much longer than the original plastic setup, even if I would replace those broken plastics for fresh ones.