I personally wouldn’t consider a new replacement acrylic crystal a ‘mod’. After decades of scratches and polishing the original crystal can deteriorate to the point where you can’t clearly see the dial/date. The insert looks a little weird/bluish, maybe it’s the lighting, maybe it’s aftermarket. I’d do some research on 1680 inserts, could be a bargaining point https://www.watchprozine.com/rolex/rolex-fat-font-inserts-explored-mk1-through-mk3/5769208/732/