I know what your thinking “why the hell dont you just buy some”
my hands down favorite sights are the white outlined U notch rears on my Hellcat. Plenty of companies make U sights but I haven’t seen any outside of the Hellcat with the white outline. I could Paint some U notches but I dont think it would be clean or last.
I haven’t located the Springfield exact Demi signs yet but I believe they are the same 60 degree angle but a wider dovetail so in theory I think sanding/filing could work
It's important that the angles are correct. Dawson's video on fitting a rear sight would be a good reference - he's just taking a little finish off to properly fit the sight, that's along way from fling a sight made for another gun down but probably as good a reference for what matters as you can get.