I was able to make an aluminum lower grill insert fairly easily.
The toughest part was removing the bumper cover,
but that is comparatively quick and easy.
I purchased a sheet of 3/4" expanded aluminum from a local truck body shop.
Cost about $35 for 3'X3'. I chose aluminum because it would be lighter, easier to bend, less likely to corrode quickly, and strong enough to offer some radiator protection.
Measuring the lower grill opening and the angles I came up with a pattern.
36" in length, 4" top section,' 4.5" middle section, 1" lower section.
Upper angle approx. 140 deg., lower angle approx. 40 deg.
Primed, painted, clearcoat. Would work easily with bedliner or any paint.
The insert fits into and around the lower opening and was secured with ss bolt and nylock nut and washer above insert.
This will not work with a front receiver and it was secured in a similar fashion from the bottom in that case.
The aluminum is easily trimmed with snips to allow clearance for tow hooks or matrix fittings.
Sorry the light is not good and the photo's don't show the insert well,
but as it is Dark Khaki, it is hard to see here.