PM'd. What bumper are you running? If its an ARB Combo bar you're out of luck as the FRBv1 will not fit. Ditto for ARB Sahara and Ironman bumpers as you'd need a 110-120mm bolt and I don't recommend bolts this long.
The original FRBv1 I designed and offered were made from 6061-T6 and mil-spec hard anodized (black). The version you show was either sourced from calamaridog or agaisin, apart of a production run they did on their own, as they had them made from some type of steel.
If your rig has significant corrosion there is a good chance the integrity of the captive nuts and/or the steel around the captive nuts on your frame are strength compromised. Remember...the brackets are just one link in the system which includes captive nuts and the material they are supported by. You may need, for reliable strength in a recovery event, to cut the front of the frame off (just a thin cap that's been welded in place); remove the OEM captive nuts and insert a suitably sized piece of 3/8" minimum thickness plate acutely beveled on each end with plain nuts welded onto the plate. This will strengthen the recovery bracket "system" along with distributing the potential load over a larger surface area.
Think worst case and you'll not be unpleasantly surprised or worse: Seriously hurt or maimed.
Dan