The screws you got from Numrich are for the thinner NM XR3 frame.
I get it,,, the OG blued screws are kinda hard to find, they do show up on EBay and a WTB ad here will bring the best results.
I have taken those Numrich screws, cut them, separate and weld in the needed length. Pain in the butt, BUT when a guy wants blued you do what you got to do.
fwiw: The weld in the middle of the screw doesn't show.
CaryC when making custom grips had blued screws made especially for him,,, because details matter.