The image didn't load for me, but I will say that if you are cartridge pleating, hemming the edge (by using the seam allowance) makes more sense than pleating with a raw edge. What you pleat shows. So, yes, fold it over. Will make the pleats pop more anyway.

On a side note, do you trim the lining on GFDs at the point where the gores start? or just let it hang down between?