I have 3 power-pac adjustable choke tubes for an old sears and roebuck jc higgins model 20 12 gauge. A long, medium and short range. I am just trying to make a couple of bucks from them but don't have a clue what they are worth. I know the shotgun itself isn't worth a whole lot but thought the chokes might bring in a few $$ anyone have any idea how much I should ask for them?? Thanks in advance!!