The only attendees that will be able to join your Webinar are the first 1,000 that arrive. That's inclusive of the host and panelists.
If you remove registration now you'll lose that database for Zoom to use while folks are connecting to the Webinar. Meaning to a degree that anybody could join your Webinar.
You could under the registration options check to see if you have a Registration Restriction number configured. If so, then you can increase that number well above your licenses account. You'll still be limited to allowing only 1,000 into your Webinar, but you'll also be able to compensate for the no-show registrations.
If you wish for folks to still view the event even past the 1,000 license you have, then you can stream your webinar to a destination, and configure Zoom to forward those additional attendees to the streamed site, instead.