Since JDT says there weren't any production factory chrome plated framesets, it's very likely the frame left the factory with paint and an owner had it plated sometime after purchase. Unless the plater had significant experience with thin tube bicycle frames, there are a number of potential issues. These include poor prep work that would normally include carefully polishing the bare steel and cleaning up file marks, plating with copper, then nickle, and finally chrome with additional polishing between steps, and finally baking the frame in an oven for several hours to reduce the risk of hydrogen embrittlement.

IOW, chrome plating bike frames isn't for amateurs.