Lister took a can of alcohol and fashioned it to look like a gun, and used it to threaten his victim.
Judge Dugald Matheson said it must have been a frightening experience for the victim who believed the weapon to be real.
Home detention was one sentencing option but was complicated by Lister residing at a local motor camp that was not suitable.
It was not Lister's first conviction that involved a weapon, the court heard. Lister is on bail for previous offending and "clearly" had an alcohol problem.
The judge remanded Lister to June 26 for a pre-sentence report and sentencing. Prison, home detention, community work and supervision were all options open to the court, Judge Matheson said.