i wouldn't.
I replaced mine, cos i wanted to repaint the bumper. 3 outta the 4 sheared, i wouldnt trust them.
Bear in mind though, that it took me nearly a full day just to remove the bumper, and i had to, erm, reshape it afterwards. Only a bit though - the bolts screw into a nut which is welded to a plate, two nuts to a plate. The problem i had was that the bolts had gone most rusty in the middle, and so sheared off there, meaning that i had two studs effectively trapping the bumper in place. A cold chisel wouldn't get through them, and i struggled to get a blade through.
In the end i cut through one on one side, and removed the other bolt, then simmply pulled the now loose end of the bumper like a 5 foot lever and broke off the remaining two studs, meaning i had to flatten the plate the bolts the bumper to the chassis. I used normal nuts to refit

grade 8.8 hardened steel, galvanised, but not welded to a plate.