It's not a silly question at all Sydie.

A Traditional Kilt is made with no rolled or folded hem. The bottom of the kilt uses the selvedge edge of the fabric as its hem.

When the Kilt is being made all the measurements are taken from the Selvedge and work up. The excess fabric is then removed from the top.

In older style military kilts all the fabric was the same width. (approx 27")with a selvedge on both sides. Each service member would be given a length of fabric and shown how to make their own kilt. Many kilts did not have the pleats in the Fell area cut away and essentially could be unstitched if necessary, the fabric reversed inside out and re-made. If the hem were torn or excessivly worn the fabric could be reversed top to bottom and the kilt re-made yet again.

In these military kilts the length from the soldiers knee cap to his natural waist would be taken and that length used to locate the top straps & buckles. Above the waist the kilt is allowed to taper back out to allow the kilt to fit above the waist.

Putting a rolled or folded hem into the bottom of an 18oz. kilt would cause the bottom to be really thick and cumbersome. It would lessen the swish of the pleats too.
A hem is sometimes put into a child's kilt to allow growth. They are also sometimes put into a dancers kilt that is made from light weight fabric to give the pleats so added weight. Other than these few times Traditional Kiltmakers do not fold or roll a hem.

The only other time I can think of when a hem is put into a kilt on purpose is when the fabric used for the kilt does not have a Kilt Selvedge. Some P/V fabrics have a fringed selvedge. Most Poly/Cotton fabrics do not have an attractive selvedge . Even some supposed kilt Wool has a less than attractive selvedge.

Not to sound harsh, but to a kiltmaker, seeing a kilt with a folded hem is a dead give away that some one took a short cut when altering the kilt or the person did not know how to take apart the kilt and do the alteration as a kilt maker would.