Can toned coins be Cameo?

You asked if toned coins can be cameo, then you went to say that you were talking about older Proof coins. But would it surprise you if I said that older Proofs were not the only older coins that can be cameo ? And yes, I'm talking about MS coins, not Proof coins.

You see, in the 19th century most of our coins, including business strikes not just Proofs, were designed to be cameo, to have the cameo effect. The cameo effect is nothing more than frosted devices coupled with highly reflective (polished) fields. But few of these coins still exist for a couple of reasons. In the first place few were actually produced because only new or fresh dies are capable of producing them. Once the die has been used a while the mirrored fields are no longer mirrored and the frost is worn off the devices, and both are caused by repeated metal flow. And once that happens they would go right on using the dies and produce more coins that would not have the cameo effect. The second reason that few still exist is because of normal attrition. Coins that had the cameo effect are worn, lost, damaged etc etc.

To realize all of this all you have to do is think about the business strike coins with the cameo effect that we most commonly see today, the DMPL Morgans. But there are other silver coins, and gold coins, and even a few copper, that have the cameo effect as well. It is even true of older world coins, not just US.

As for question about toning, yes the mirrored fields and the frosted devices can still be seen through the toning. All coins tone, from the moment they are minted they begin toning. So any coin, Proof or business strike, with the cameo effect, unless it has been freshly dipped, has at least some degree of toning. And of course some have much more toning than others. And it is only when the toning reaches an advanced degree that the cameo effect can no longer been seen. But even some of those coins can be or have been dipped to once again reveal the cameo effect that was hidden.