It's not like he would have had to break out a metal detector to find it. he could have located it with the force and brought it back in 5 seconds all while moving Vader.
(EU warning)
Green definitely for Luke. Blue is the color of Jedi Guardians, those that manifest the force through primarily physical abilities, very much the path of Anakin. Green is for Jedi Consulars, those who are more meditative and mindful of the mysteries of the force itself. Early on, Luke was more about raw power, but as a sole Jedi attempting to either discover the nature of the force with no master or to rebuild a new order, Green seems more appropriate.
(EU warning)
Green definitely for Luke. Blue is the color of Jedi Guardians, those that manifest the force through primarily physical abilities, very much the path of Anakin. Green is for Jedi Consulars, those who are more meditative and mindful of the mysteries of the force itself. Early on, Luke was more about raw power, but as a sole Jedi attempting to either discover the nature of the force with no master or to rebuild a new order, Green seems more appropriate.