Force reinstalling latest version

When clicking on Rollback we get the list of available versions, including the latest one currently installed (if the plugin/theme is fully updated).

Will this force reinstalling the latest version on top of existing one if it already exist?

I recently got some server errors when updating a plugin and some files were missing, causing issues with the plugin. I was wondering whether, in such cases, I could use this Rollback option for just updating a plugin/theme that is already in latest version but might have some files missing or corrupt?

I presume this action will overwrite all existing files. But what about unwanted files that might be in there if a site was hacked for instance and contains malware or hacked original files? Will this action completely wipe existing folder or simply overwrite the same files?

Thanks!