I think you can be pretty confident those will have conventional right hand threads. First, hex-head bolts with left hand threads are very, very unusual, and second, both of those fasteners (45 and 57) have to be undone in common service operations, not just overhauls, and those service operations are the same on this machine as on many, many others. To use a left-hand thread on a design which is just about universal on mowers, both push and ride-on, and which is always right-hand, would cause close to 100% of routine service procedures to result in stripped threads. The manufacturer who did it would be laughed out of the industry.
