Source is, you can shine a UV light on your cab and where the cadmium-plated screws have oxidized, there will be small particles glowing.
I'm not a science guy so I'm not going to pretend I know much about it, but my partner has a job working with hazardous materials in artefacts and she poked around both of my Neo cabs. The carriage bolts and a couple of smaller screws in the coin chute lit up.
Apparently cadmium was a common plating until the turn of the millennium as it helped prevent rusting. Until rust forms on the screws and they become highly toxic. Control panel would get the most wear and tear on the machine, so it's the most likely place to use the coating.
FWIW, my cabs only had the oxidization on the underside rather than the bolt head, so playing the machine should be fine.