I have a choice of two sternlegs for both sale out of a 33' bayliner 5 litre V8's, is there an easy way to tell what rotation, as i want a standard leg not counter rotation to suit my single engined 23 sea ray on the transom plates were the serial number OD532577 (left hand leg) OD532559 (right hand leg)

Left hand rotation is easy to see ,look at the propshaft end ,were the nut secures the prop ,in the center ,there is an L stamped in or LH ,that means its a left hand drive ,that can only be used as a left hand drive .
RH drives has nothing stamped in .

Thanks for that, I presume that the Right hand rotation is normal operation

Yes ,RH rotation is also called clockwise rotation ,and is the normal rotation for a sterndrive .(as seen from behind )