I have a sample of that exact same kilt. Judging by the result of the fabric burn test I did, it is NOT PV. It is acrylic of average quality.

There is a definite difference if you take a thread and burn it, and stretch the melted end while it is still hot.

Acrylic turns an orange-yellow color, PV turns black:



The yarn on the left is Marton PV, Asian acrylic on the right.

I suspect many of the so-called "16-oz PV" kilts are neither 16-oz or PV.