Thats not my truck in the photo...I found it online and just posted it so I can reference the flares that I am on the hunt for.
Those factory flares require holes to exist in the fender already. Otherwise you have to drill them, and add the supporting
brackets and hardware.
I've got the fiberglass aftermarket flares on my BJ74 I like them. They are screwed to the inner lip on the fender.
They will hold crap and moisture in behind them. What part of the country are you living in? If you live in the desert or
dry area not a big deal, but if you are in snow/salt zone then you have to think about it.