2)Can I get a real Bo-mar rear put in?
Yes the slide uses a LPA sight cut and Bomar
offers them, The Other sight company does too but... Bomar make one for the cut you have.
It will be as tall (your front sight is .175 high )
3)What is the front sight cut for?
Para's own. they seem to vary in depth so you may be thinning the dovetail some to get it in, try to work on one side only. that should keep it strait.
geo ><>