Most of the 1640s were drilled and tapped from the factory, but not all of them! I have one where the rear holes were not aligned properly to the rest of the action. I couldn't tell you for sure if it came like that from the factory, or if some genius did that work afterwards -I would guess the latter. I had Farrell Industries cut a custom pic rail for it and that has worked great. As far as I know, none of the models before 1640 were ever drilled and tapped from the factory -those were all 98 and 96 Mausers.Hello All - I'm looking for a Husqvarna to send to JES for a rebore to .35 Whelen. I'm lucky enough to live in-state and not far from Simpson's Ltd. Is there a model I should focus on if I'm concerned with mounting an optic e.g. bolt throw, drilled and tapped receiver. Thanks all and have a great New Year.