I could do it with the latest (although it might be 2 updates ago by now) Gibbed Save Editor. Go to Raw--> Mission Playthrough --> Mission Data (TVHM 2nd row). Scroll down to the mission that you want to be edited (the names are very obvious), change the status to ReadytoTurnIn and check the NeedsRewards option.
Oh ya, you can change the GameStage option to 50 if you want a level 50 reward. This is tested and confirmed. I have now gotten 2 additional Laws from the 'Won't Get Fooled Again' mission.
Sidenote: The NotStarted status option seems bugged for me as the quest giver can hand me the mission but I can't accept so change it to Failed if you want to restart say the "Doctor's Orders" to farm Jimmy Jenkins.