Students cannot view the a file in Course Files outside of the restriction dates, if the student availability date restriction is applied. Students date restrictions are applied.
In other parts of Canvas where the file is attached (e.g. Modules, Assignments), students will be able to see the name of the file only, if it is linked in another area of Canvas (such as Modules or Assignments), but if the file is outside the available dates.
If they click it, they will see a message stating that the file has been locked and cannot be seen until the set date.