Better buy a few dozen carbide drill bits. Drilling into the roll bars ain't easy.You could add. Use the part itself for a mounting template then PRECISELY drill and place rivnuts through the existing metal bar. Not a huge project, but might need to rent a hydraulic rivnut setter.
Same for the OP if one hole doesn't have threads of they are damaged. Drill it out carefully and install a new rivnut.
No. It help the chassis resist large loads from terrain.
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