It passed at last annual but I haven't checked it yet this year; I'll follow up here when I do.

Last year I didn't notice the wear on the angle rivets but I was also a new aircraft owner and I've become far more observant as I've gotten to know the plane better.

Question
 

What tool??? I never received any tool like this with my kit. Anyone have a photo??

I'll bet you have it, here's a picture from the MM p.3-15 as previously mentioned by jrtens:

Mine came with the final documentation and placard package.

Checked last weekend: yes, all of the bushings (both those in the spar and those in the fuselage) are within tolerance based on testing using the tool that comes with the kit.

wear of spar rivets
 

It is really hard to be sure what you are looking at in close-up photos but it appears that the worn rivet heads are on the front side of the left wing spar. The left spar slides into the fuselage in front of the right spar, so the wear line on the rivets and the angle seems to have only the possibility of lining up with the edge of the rectangular hole in the side skin of the fuselage. As Bruce mentioned, when I first installed my wings into the fuselage there was a lot of scraping. The precut rectangular holes in the side skins of the fuselage were a touch too small and scraped against the spar. I had to file out a significant amount of material to get the spars to go all the way in. I didn't measure it but I'm thinking maybe 1/16 to 1/8 inch had to be removed. This kind of scraping vibration seems consistent with the wear pattern in your photos.

Unless I have misinterpreted your photos, I don't see any other possibility. I'm a few weeks behind, so hopefully you have already fixed it.