What size frame? It might be 650c wheels (not 650b), to help prevent toe overlap in smaller frame sizes - think 50cm and smaller.
If they turn out to be 650c wheels, I'd pass and look for a bike with 700c wheels. If you're 5'7, you don't need a 50cm or smaller frame, you're probably more like 52-54.
Nothing wrong with 650c, but it's harder to source tires and tubes in this size, and they ain't cheap.