In the 1941-42 period some very well known ships were plain on one side and patterned on the other, eg Tirpitz and USS Lafayette (ex-Normandie) but this was the time that the Admiralty was using class-standard patterns on Royal Navy Ships and most of those were mirror image patterns. Breconshire was the most militarised of the "Glen" fast freighters and it may have been given a pattern which was intended for the rest of the sister ships next time they were docked, so I painted a mirror pattern on the port side of my Breconshire (converted from John Laing's unarmed Glenorchy - sadly the Glenorchy kit is no longer available).
I do have a number of kit-built engines, trucks and coaches running on my OO railway with different liveries on the other side and next time you are in the Swansea Industrial Museum look at the end door private ownertruck on the tippler....