$500 is for gun parts. Scopes are still controlled under ITAR, AFAIK.
Interesting, I found a summary of itar that says riflescopes not made to military specs (and non combat shotguns with >18" barrel!)
18
Tuttle Law 2011
United States Munitions List (USML)
§ 121.1 General. The United States Munitions
List.
– Category I—Firearms, Close Assault Weapons and Combat Shotguns
(a) Guns under caliber .50
category excludes any non-combat shotgun with a barrel length of 18 inches or longer, BB, pellet, and muzzle loading (black powder) firearms.
Does not cover riflescopes and sighting devices that are not manufactured to military specifications.
Excludes accessories and attachments (e.g., belts, slings, after market rubber grips, cleaning kits) for firearms that do not enhance the usefulness, effectiveness, or capabilities of the firearm, components and parts.