I had 2 of the same, used one and the quest came up. Then I tried to use the second one and it said something like Already have this quest. After I sent a companion on the mission I tried to right click the second Mission item and this time it brought the mission back up for me again to let a second companion run it. I haven't seen the mission pop up again randomly in my mission choices. I would assume that the items are therefore one time use and you can do the same quest over and over again once you get it off your mission selection. Hope that helps, i couldn't find info on them anywhere either so if someone else knows differently then by all means jump in.