My guess is that it's a repro cabinet too but it's held together better than most of the ones I've seen, but I'd have to see it again, it's been close to 6 months (and about 30 machines) since I saw it.
EDIT: Originally he thought he'd taken it to the Singer store and had them upgrade his machine with a motor, but it looks like what they did was "Trade" for a repro machine. Which in retrospect means the treadle cabinet may be original. I might have to go take a look at it again. I originally left it there because he had to dig up the treadle parts that he'd taken off and stored because he didn't need them with an electric machine. I said when he found them to give me a dingle. I heard from him last week.