The covers are a vintage Micarta from Poland that was reportedly used in elevators in the 1950s or ‘60s. It came in an 4” diameter rod that Eric crosscut into disks the correct thickness for the scales. The dark spots occurred randomly in the material. Less than half the knives had dark spots, some had them on both sides, others only on one side. I posted some pics that Eric had shared with me of the whole process a couple pages back (
here’s a link to the post).
Sorry you missed out on the Guardians knife.

While all the Micarta Guardians knives are spoken for, I do have a GAW going in the Guardians thread for a 1-of-1 variant that Eric put together using leftover liners that had already been stamped with the GL-24 stamp. It’s open to anyone with at least 25 posts in the Guardians thread, so you should definitely qualify to enter.