Look closely at the two halves of this apron and they are not identical. That is not a mistake, and it is not carelessness.
Ornament of this kind was never meant to be mirrored. A shell on one side is answered by a scroll on the other; a leaf turns up here and down there. The composition balances - the visual weight is the same left and right - but the detail is not repeated. That is what stops it looking mechanical, and it is the single clearest difference between hand carving and anything reproduced from a mould.
The discipline is in the balancing, not the copying. Our carvers set out the two halves from separate drawings and then check them against each other by eye at a distance rather than by measurement up close, because balance is judged from across a room and symmetry is judged from a foot away. If one side starts to feel heavier, weight is added to the other in a different element rather than the same one.
The result reads as lively rather than repetitive. Photograph the two halves side by side and they will not overlay - which is exactly the point.