Just thought I'd point out that sometimes you can see the specific dye more clearly than the little circle shows. If it's an item you have yourself, you can select the "dye" command from the drop-down menu as though you were going to change the dye color, and the current one will have a green checkbox in the dye selection window.

That's only available, however, if it's an item of yours, that you would have the option of dying. It's not available when looking for items on the MarketBoard, selecting item quest rewards, inspecting someone else's cool-looking outfit, etc. So I agree that having it listed in the item description tooltip would be better.