How to Tell if a Peace Dollar is Dipped?

You're certainly not alone in that thinking ! But, when it comes right down to it, as a general rule - they can't. The reason they can't is due to the nature of their luster.

Ya see, all coins, even those made of the same alloy, have a different, and sometimes even unique, type of luster. And it is their differences in luster that dictates the various ways, patterns, even colors at times, that they are capable of toning - or not toning.

To put it into an analogy, where bluebirds is used it replace Peace dollars, it would be kind of like saying - I wish bluebirds could be red or green.