I personally couldn't notice either from pics but a S shaped spine could indicate a few different diseases as well as a natural deformity but he looks healthy
That was the smallest fish of the group when I got them. It has since caught up in size and is the only one with the speckling and color in its lower fins. Always had the deformity in my care. It's much easier to notice in person. It's by far my nicest bass as far as color goes though.