you cant set an alarm,,, as the pressure will go up and down according to the pressure in the inlet manifold

what you are seeing is what we call base pressure,,, this is the pressure in the rail at atomspheric pressure

if you run 20 psi it will show 73.3 psi (53.3+20)
if you are on over-run and the inlet pressure is now -10psi, your fuel pressure will be 43.3psi (53.3-10)

and no you cant tell what pump you got