Delta 4 swivel joint corrosion, what to do?

[steelwindmachine]

I have two Delta4 regs with the swivel hose connection. These regs are about 8 years old. One of them has been on 25 dives, the other about 50. I was inspecting them last night and pulled up the swivel joint boots to inspect the ball joint. The joint swivel action is still smooth, but I did notice some dark blemishing on the ball itself.

These blemishes could not be removed with a nylon bristle brush. Should I be concerned about this? Or, just periodically check them and when they become pits or the joint becomes notchy, then replace?

Any insight would be appreciated!

Thanks!