Velcro adhesive can get kinda nasty usually after you feel off the Velcro most of the adhesive stays on whatever it was on the. You are doing to either scraping or heating and wiping to remove and at that point could very easily damage your finish. If the adhesive does decide to stay intact it could then damage your finish while removing. I would skip wanting to stick them on the side of your unit. Or like said above try some suction cups. Probably fall off more then stay up but could be worth a shot.
2014 Sierra 365 SAQ
2014 F350 CC DRW lariat ultimate kodiak brown, 65 gallon titan fuel tank, bak flip box cover, many mods to come.