Welcome, Michael, from the Seacoast of New Hampshire (USA).

Cacunn's question above might help answer the question. Check the way the aprons are worn. Also, usually a kilted skirt has very shallow pleats (sometimes the underpleat is about the same depth as the part of the pleat that shows. A kilt, most always has quite a deep under pleat (usually 8cm or more) and the upper pleat is smaller.*

You've come to the right place to get your answer. Keep checking your thread.

*Unless, it has box pleats, then there is a whole different look and measurement.