The black bolt comes with a new clutch. When my Boost clutch was replaced after it came off the dealer gave me a black bolt with the new clutch. It's just for installation like everyone is stating. Use it to torque to 140 then install silver bolt to 110.
I seen this picture in a recent thread on another forum. According to the poster, it shows from left to right, new bolt, old bolt, and installation bolt. I'll have a closer look at my black bolt in the morning to see which style it most closely resembles... I was assured I would receive an installation bolt and the 7528304 bolt (which people are saying is black). 7528304 is apparently very recent and superseded 7328193 just in the last week or two. I'm confused because it seems like I should have received two black bolts, but one of them is silver.