Welds look a bit sloppy but prob will hold up. None the less I would definitely add some bracing. Having a guy standing on rock rail is bemusing but doesn't tell much. Put a Highlift or something under it for more real world test. If there are any concern doing it then its not a real world rock rail because when you need them they will exposed to likely much higher loads. I would specifically concentrate on either/both ends since that would expose mounting arms to highest stress. In real world we don't always get hang up smack in the middle. Do we?
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