A stitch across the bottom of the fell?

[The Wizard of BC]

Is this the sort of line you are describing?

You can see a line of machine stitches just below the Yellow stripe of the Kilt.



If this is indeed the line you are describing then yes, that is the Steeking line on a machine sewn Kilt.

This is one of the most important elements of any well made Kilt. It cannot be skipped or omitted if you want the pleats to remain parallel and to hang straight.

Because I machine sew my Kilts the Steeking line is visible on the outside.

In a hand-sewn Kilt the Steeking is done from the inside and is not visible.