Fortunately or unfortunately for the intended story, those missiles would already be dead... as they were not maintained for likely literal decades or more.
All military hardware have shelf live span, if they were not constantly maintained or refurbished periodically... they basically will quickly turn into non functional hardware or worse... malfunctioning hardware, and some cannot be refurbished past certain point and has to be literally... destroyed like garbage.
By the time suggested in the story, none of those missiles would even have a remote chance of functioning.