You said the sides seemed a little different, but I'm taking it that they looked like normal stockinette?
I wonder if they might have run some of the end border ribbing all along the sides. That may keep it from curling too. Ribbing is a non-curling stitch, but it can look pretty much like stockinette because the purls sort of recede into the cracks and all that you see are the knits. I have never tried doing ribbing up the side of a scarf and I'm not 100% sure it would stop the curling, but I think I would try a very narrow trial "scarf" with any ole yarn and see if it does. Merigold