Not necessarily. Many climbing sports of bush roses are once-flowering. Many of the old cl HTs were once flowering. There are once-flowering climbing sports of Mlle Cecile Brunner and the original climbing sport of Iceberg was once-flowering until a further mutation was found which flowered repeatedly. That one has pretty much replaced all the once-flowering Cl. Icebergs in commerce. Lady Carolina repeated at Limberlost Roses in Van Nuys, CA years ago. If the climate and conditions support it, it will repeat. If not, it likely won't. But whether it does or doesn't, once-flowering doesn't prove it's a sport of a once-flowering rose.