When I got my Silvertip, I indicated that I wanted antler burl fastenings for the limbs, so my limbs came with the fixed bolts, and also with a spare pare of the ugly black knobs. My understanding is that was the way it had to be if I wanted the Silvertip antler burls, although antler burl fastenings are available other places, I guess, that have the bolts built into the burls themselves. I've never had any problem with the fixed bolts, and I guess never gave it a thought until I read these posts.