Yeah. I've never seen anyone use "inflammable" to mean "nonflamable," but I've definitely seen "nonplussed" used in place of "unbothered."
Novels are a good example cuz it's reasonable to assume that the author and their editor know what "nonplussed" means... But what if they elect to use the other meaning for philosophical or aesthetic reasons?
What about an older, cooler-looking silver dragon?