The 20-year-old left back, who has been on a season long loan deal with The Pilgrims, has signed a two year contract at Home Park.
Gilbert, who had signed a new one year contract at the Blues just prior to his loan move to The Pilgrims last July, has helped steer Argyle to the brink of a place in next seasons Nationwide First Division, making 36 appearances and scoring twice in their push for promotion from division two.
