The sprocket is just a sprocket attached to the (charging) rotor. No damping or damping mechanism to come apart like a Big Twin. But the nut has been known to loosen and it can come off and rattle against the side of the primary.
I’d recommend pulling the primary cover just to be on the safe side.
My money is on piston slap. But it can be hard to pinpoint a sound on these noisy beasts.