The “whole template”? Do you mean the entire theme? Some people use “template” when they really mean “theme”. In other CMS systems they may be the same thing, but not in WP.
If your theme came with a front page template and you’ve modified it, clearing your customization will only reset that one front page template to how it was originally shipped. Your customization of other templates in the theme will remain unless you explicitly clear those as well, one at a time. There actually is no obvious way to clear all customization of all of a theme’s templates all at once.
I think the easiest way to do a full theme reset of everything would be to change the theme’s name (untested and not what you want anyway. I’m only mentioning it in case it helps someone else landing here by search).