I've been searching for a while for a way to lock the tailgate of my 1985 F250. There are locks available that cover the tailgate handle but they're expensive, are not available specifically for my model F250, and do not seem thief-proof. Somebody suggested that I "rivet" a hasp and use padlocks. Unfortunately, that would mean I'll have to drill holes in the the bed of my truck. Can someone give me advice what I can do to lock my tailgate.