well i have never taken one off a f-body, but i have taken quite a few off other GM vehicles and there seems to be a pattern.
open hood, may be some plastic push clips holding on the top
take out screws or retainers holding lower diflector on
take out screws or retainers holding inner fender liner to front bumper.
look inside bumper after pulling back fender liner and where the bumper cover meets the fender there should be one or two bolts holding it on
should come off, but if not search to see where its still held on.