I would suspect the "missing tooth" is factory. what type of stepper unit is it ? "increment/decrement" like a bonus unit -or- "full reset" like a player-up unit?

Yeah those rivets look pretty worn , myself I would probably try to fill them with solder but apparently they can be replaced https://pinside.com/pinball/forum/topic/gottlieb-stepper-switch-rivet-tool-help-pls

That is factory.

The ball in play unit is a step up/reset unit.

That is on the edge on the rivets. You could try flowing solder into the grooves and smoothing it out.

Silver solder is harder and will likely hold up a little better in rivet repairs.

https://pinside.com/pinball/forum/topic/hearts-and-spades-always-a-ball-short#post-4519175

/Mark

Yes factory.

Rivets need fixing for sure so options are:

1. Flow solder, silver is harder agree. Then use dremel wirebrush to smooth.

2. Next-level: replace rivets with new ones from PBR but you’ll need a special (expensive) tool for this (or some do manually with cheaper methods). Lots of threads on pinside on this - best to use google.

3. Next-level: replace disc (sometimes Steve at PBR has them in stock - just ask)

You might want to check the end float on your toothed wheel. I recently had to rebuild those rivets because the spring-loaded snowshoes that ride over them were scoring the disc itself too because there was no end float. So I set it so there was just little end float so in turn, the snowshoes were not scraping as much so as to give more wear in future.

Well, you don't really need an expensive special tool to do it, just a press will do it. But it's not an easy job. You have to desolder the entire disk and then hope that you get the right rivets. I tried this on a Gigi, ordering the rivets from PBR. MikeO on here has the press and was going to do the work, only the rivets ended up being the wrong rivets. In the end, we ended up flowing solder into the grooves and smoothing it out. The game is yet to be finished but it's far enough along that I've been able to test it and it works fine.