Jackboy has always insisted he's innocent in his gun possession case, and now prosecutors at least agree he shouldn't be charged ... because they don't have the goods to prove he's guilty.
Jonathan L. Adams, the Monroe County D.A., tells TMZ ... his office decided not to move forward with charges against the rapper "due to our concern regarding being able to prove [Jackboy] had actual knowledge of the location of the firearms."
Adams pointed to the same issue cops identified in their initial report ... that a passenger in the backseat claimed to be responsible for the 2 guns found in the glove box.
Jackboy's attorney, Drew Findling, says, "We told you early this year that Pierre Delince (Jackboy) was innocent of these charges." He added, "We are very much appreciative of them making that important decision."
TMZ broke the story ... Jackboy was busted in March after cops pulled over a vehicle in which he was a passenger, because the driver had trouble staying in his lane.
When cops searched the Lambo SUV they said they found 2 unregistered handguns in the glove box next to Jackboy's seat.
Cops say the rapper told cops he didn't know there were guns in the whip. He was ultimately arrested and booked for possession of a firearm by a convicted felon. But, prosecutors now say they don't have evidence Jackboy knew the guns were there.