I've been overhauling these units (i.e., cleaning the corrosion on the brackets & springs, whittling down the gear so it turns easily, etc.), and of course I lost a few of these clips (I was able to cannibalize them off of an unused coin unit) - so I would like to get a few of these as spares.
I asked Steve @ The Pinball Resource about the Williams clips that he has, but he said they would not fit Bally (he does not carry the Bally ones). I see the 3/16" @ Marco's:
https://www.marcospecialties.com/pinball-parts/12-6227
I can also get a 25-set of different sizes of these clips at Amazon, including 1/8" for about $8. Steve recommended that I get an assorted set of clips, which would have many sizes, but I don't see anyone at eBay or Amazon selling them. I don't think my local hardware store carries these clips, but I guess I could try.