[Yardstick]

Never a double stitch on the outside of the leg but sometimes a double stitch on the inside. This is based on a quick scan of vintage 501s on eBay.

And actually the outside doesn’t have a visible stitch at all. Levis uses a butted seam rather than a folded seam (not sure if these are correct terms) on the outside of the leg that hides the stitching and looks smoother.

[jeffc]

Thanks. My memory of long ago isn’t what it used to be!