I have thought about this a lot. An appraisal does not guarantee that you will be compensated that amount in the event of an incident/loss.
What you and I know your vehicle is worth and what an insurance adjuster will pay are sometimes worlds apart. I would take lots of pictures of the car and keep any pertinent paperwork related to the build/restoration. Unfortunately if you were to have an accident -regardless of who is at fault - they might just see an old 80s beater. They might not even care about an appraisal.
TRUE STORY: From 2005 through 2007 I spent thousands of dollars fixing up a 5.0 Mustang notch. I finally got it just the way I wanted it (It was beautiful - - and ran 12s!). A teenage boy ran a stop sign and I T boned him in his Blazer. Long story short, his insurance company "totalled" my Mustang and offered me $1600!! I went round and round with numerous people at his insurance co. and even tried to "buy the car back" from them and offered the title and the keys if I could just have the carcass. I never convinced anyone there that the car was easily worth $5000 or more. They absolutely refused to let me keep the car. In the end I had 2 factors working in my favor: #1 I had the wrecked car on my property so there were no storage fees accumulating, and #2 I was very, very patient. I waited them out and I think after a while they were tired of dealing with me and the letters, and the phone calls etc. They let me "strip" what I wanted off the car before they hauled it away and cut me a check. I think I got $2400 plus the engine, transmission, rear, wheels, seats, and a few other goodies.
LESSON LEARNED: I have collector car insurance now. The cool thing is it is a name your price/value and then you pay premiums accordingly. Agreed on value. The bad thing is there are restrictions about driving to work/errands etc.
Hope this helps
James