They replace the webbing and restitch the tag back on the new belt. They called me up an said their was nothing wrong with the retraction/lock so they cleaned it and sent it back with the new webbing. Not sure if they would have repaired the actual lock. My little brother had bought me the Cruiser Corp replacement seatbelts a few years ago, they never retracted correctly and did not work with the original buckle. Very happy with Safety Restore.
If you were doing a full-blown restoration, I would reach out to
www.timecapsulela.com. Eye candy on their website and Instagram.