Tips on buying a used Aimpoint T1?

I have a chance to buy a used T1 from one of my law enforcement buddies. The fact that he is still an active cop makes me not worried that it might be counterfeit, but what other things should I look for?

I plan to check it for these criteria:

  1. Brightness at all visible settings
  2. Positive clicks in the power settings.
  3. IIRC the windage and elevation wheels have positive clicks also, right?
  4. Condition of O-rings
  5. Condition of lenses
  6. Condition of mount points if it doesn’t come with a mount.
  7. Clarity of sight picture with no halos or anything in the sight window.
  8. Condition of battery contacts
  9. Condition of mount, if any

After LAV’s torture test of a T1 on his Daniel Defense carbine I tend to think there isn’t much to be concerned with as far as buying a used T1, but have I forgotten anything?

Its a T1, if it works, you’re good. Buy it and go shoot it!

And if it stops working, send it back to Aimpoint for repair/replacement.