Example:
Corporate Metropolis has a Plasma Cannon in Stock, which is level 10, so they can't install it.
In Dock -> Weapons -> Upgrade it's not shown, because they can't actually do the upgrade.
In Commodities -> Buy its not shown by default, because it's a Weapon.

Result: Player will miss the Item unless they switch to "Show Dock Items".

Suggested solution: show the item in Dock -> Weapons -> Upgrade/Install in light gray text color and offer to sell it without installing.