Well, rebuilds like this are always risky, and you don't really know what's the right thing to do. I think that deciding to sell it was the right thing to do.
If you hadn't decided to sell the car, the right thing would be to call your insurance company and see what they have to tell you about your situation. If you didn't like their opinion, you could've tried different insurance companies. The easiest way to find an insurance company is by comparing auto insurance quotes online.