I called Fender at this number, sat on hold for a lonnnng, lonnnng time, and ended up talking to a real person (which was cool). As it turns out, the part number (and size- #6-32 x 7/16”) provided by the Fender Service Diagram is (allegedly) correct for the CURRENT model Duff Bass which is a MiM. However, mine (also MiM) dates at 12/2016. Apparently, a while back (don't know when for sure), MiM basses used metric hardware and two or three years ago they switched to imperial hardware. The CS rep didn't know the exact size that the saddle-height adjustment screws used to be, however he is looking into it more and claims he will contact me with the "correct" size.
Based on all of this, I measured them, and it came in at about 12mm length and around 3mm diameter. I looked around and ordered some M3X12's. I didn't see anything offering thread pitch options. We'll see how it goes.
Thanks for all the suggestions.