I still use my Models 3904 and 3913. Where can one find quality night sights for them?

Trijicon still makes them. Join Dvor, it is Optics Planet's clearence sight. You can usually get a set from $60 to $80.

Thank you!

Meprolights makes sets for 3rd Gens, too. The front sight is taller than
OEM--at least for 6906 and 4013TSW. Haven't seen the Trijicon version,
don't know how they compare with OEMs.

If the OEM sights shoot high for you, the Meprolights will bring groups down.
If they shoot low, the Mepro's will shoot lower.

I ended up replacing the rear sight with adjustable LPA's.