Both models have the same factory sights (109070000 & 107920000).
For night sights, Trijicon lists the same sights for the 69xx and 3913/14 (SA08 and SA24), which I think are the best ones available.
XS 24/7 night sights has the 69xx series/4013TSW as separate sights from the 39xx/59xx/CS9 sights. These will be cheaper and have the fastest sight/target acquisition, but will be a looser fit and more 'combat accurate' than the Trijicons. In my experience, I would advise not removing anything from the sight bases at first, and use the red loctite as per the instructions (not too much though).
There are also the Meprolight 3900/5900/6900/4000 night sights, which are the cheapest in price. These are a universal 9mm/40SW 3rd Gen sight, and I personally have no experience with them. I have heard reports of these shooting low with the shorter barrels here on the forums.