Do you have the sense that the original would have been done like you did, all at once, with a goal of making a tunic from a (random) pile of scraps, or, could it have been assembled a bit at a time when one item was ripped and repaired, and then another, and finally someone turned it into a tunic long after the first two bits were put together?
Definitely an assembly all at once, I'd say. I can't see a reason for sewing arbitrary bits of used fabric together arbitrarily to one day turn it into a tunic, and it was definitely not a normal tunic that was just patched up. So I'd say that yes, someone sat down with a pile of scraps and went for a tunic.