True, they use epoxy to 'glue' the fiberglass covers onto the brackets. What I did with mine when they came loose was to drill a hole from the back through the bracket holes and through the cover. Then used a countersink bit on the cover surface so I could use flathead 6-32 stainless steel screws, along with plastic insert lock nuts. I only used two screws per panel as the panels aren't that heavy and many of the epoxied brackets were still holding. I've seen people use large 1/2" bolts but I didn't see the point of that with mine and didn't care for the look of 4 large hex head bolts on the surface that my friends shop did to her front cover.
The 6-32 screws are small enough that they're hardly noticeable, especially since they're flush with the surface, and in an accident, the cover would pull right off the screws so it wouldn't be damaged much. And of course, the brackets have anywhere from 2-4 holes which could all have screws put in them if someone wanted more holding power.
Here's my blog article on how I did my rear covers. I'll do the front cover the same way when I get to it, as it happens, this week. It's been on my '2do' list for a couple months now:
Body Work... | Chaos Leaves Town
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