Some say that the way the piston is installed as standard in Jabs is actually incorrect as it offsets the gudgeon pin to the wrong side, so there is is some logic in rotating them 180 degrees
TBH Jabirus have gone through so many changes, some seemingly undocumented and also been subject to a multitude of 3rd party mods to supposedly fix things I reckon it would be a hard job to find 2 Identical in service engines.
edit just read Thruster already mentioned the offset, its odd, but Jabiru has never explained