I think Silver Moon is a good guess.
Here are some other ideas: City of York, Gardenia, Jersey Beauty, Baltimore Belle, Nanette, or The Garland. Jersey Beauty looks quite similar, but it has fewer petals. Several of these are about the right color, and several have glossy foliage characteristic of a wichurana rambler. The Garland, Nanette, Baltimore Belle, and Gardenia appear to have too many petals compared to your rose. City of York is a possibility, it was released to the US after WWII. It definitely has highly glossy foliage. I grew it when I lived in NJ and was delighted with it, even though it did not repeat. Whatever rose it is, it's great looking rose.
