How can you unhide the file extension of an application created in Automator?
I believe that the System automatically by default hides the .app filename extension regardless of unchecking the Hide extension checkbox upon being saved and the Hide extension checkbox on the Get Info sheet will be grayed out when the .app filename extension is present. You'll need to send feedback to Apple on this one.

The only way I know how to override this in Finder is to check the Show all filename extensions checkbox under Advanced Finder Preferences. This of course then shows all filename extensions that are set to hidden, not just the .app filename extension.