Insurers tend to "estimate" rather low, leaning sharply toward after-market parts or parts from junk yards. To be fair, when you are driving around in a 3 year old car, you HAVE a collection of used parts and replacing your used fender with a used fender is not necessarily a disservice. Yet people tend to insist on new because, typically, policies provide that. People tend to insist on that even though, if they were paying for it themselves, they would go for the $200 fender from the junkyard rather than $600 new, if given that option and a reasonable chance to inspect the junk yard part.
But insurers are also going to struggle for a while on what it costs to do body work on a Tesla. There are not a lot of junk yard parts available yet. Aluminum is notoriously more difficult to work with, and a lot of body shops don't know what they are doing yet. The ones that do may charge substantially more, and get it, because there is not a lot of competition. Insurers will take a while to get up to speed.
