The answer is YES! You can now restrict users from modifying their registrations at any time.
Here Is How To Do It-
Step 1: Navigate to Events> Specific Event's "Events Settings" tab. On the bottom of the page, locate and toggle on "Allow Edit".
This will prevent guests from making edits as the edits options will be grayed out and unresponsive.
Admins will still be able to edit anyone's registration through the 'Guest Manager,' even if the user can't edit their own registration.