The cone and bolt are two pieces. They act like one, but there are threads inside the cone that the bolt is threaded through, then the smooth shoulder of the bolt just allows the bolt to rattle around in the cone.
I might have a set of A4s as well. I am picking up a replacement set of A5s for my boat soon. Last set I literally wore out.
Careful of cones and parts on ebay. Most are the older style that requires a lock washer. Newer style setups use a nylon lock nut behind the outer prop. If cone has just a hole for prop tool, it's the older style. If a slot, it's the newer style. Later prop tool comes with wrench/long rod for cone/bolt, and nylon lock nut tightening tool that slides over long rod.
Glenn (Wizard)
"The Reel One"
26' Billfisher