Disney pin trading turns 25 this year, and whether you’re a casual collector or a serious sleuth for rare finds, the hobby is thriving.

For the first time, Gap Inc.'s Old Navy division has partnered with Disney and its band of fabled characters on a collection ...

instead of hard enamel, which would be polished flat. Mickey head patterns pressed into the backs of official Disney pins go all the way to the edges, while knockoffs may have a border.