Ah to the body, never thought of that. I have a metal plate bonded underneath mine I was going to fab it to the chassis somehow.
I like your idea better if you are sure whatever is bonded to the body to latch the velcro to will never come off. Also maybe having them go both ways to prevent sliding out. Although I see the only space to attach anything would be fender-side and top, at the front there's the headlight washer and minimal space at the hood side. Could be wrong, just thinking.