If they're just discolored but still smooth, you could probably load them as-is. It wouldn't hurt to tumble them, though - once they're smooth and shiny, you'll be better able to see if there's any actual corrosion present.
Do not know why you would ask that question if you own a tumbler. It seems easier to just throw them into the tumbler than to go online and ask about it. Tumbling would not hurt them even if they did not "need" it. When in doubt, tumble.
