Remember my old scale that only weighed in ounces?

Exactly, a simple sign is basically free advertising every time you roll down the highway.

Ever try a mix of heat and penetrating oil? On a stubborn one like that, I warmed the metal around the hinge with a heat gun, not too crazy hot, then let it cool a bit before hitting it with some PB Blaster. Let it sit overnight, then gentle pressure back and forth with a long pry bar. Sometimes tapping the pivot pin with a small hammer and punch can help break the rust bond too.