It depends...I've seen Model 67s with pinned front sights as well as with fixed front sights with or without the (red) ramped all as standard factory offerings. If you have one with a pinned front sight, then it's no problem to replace. If you have one with a fixed front sight with a red ramp, Meprolight makes night sights for S&W revolvers that retail for under $100.00 that replace the rear sight blade, and provide a night sight for the front sight (you have to replace the red ramp with the front night sight). I've seen ads for some gunsmiths that will drill and install a night sight for the front sight only, but it's a fairly pricey option - i.e. not that "easy".
Regards,
Dave
