I use Hagerty on my 69. There are some very basic rules but other than that it's not really an issue.
I told them what it should be valued at and sent pics and they agreed.
Most collector car insurance programs have it available.
Never heard of it for "regular car" insurance.
What I thought was weird about Hagerty, was, I read online where they stated that they did not have a mileage restriction. I called them to clarify some of the policy details, and the rep told me that I would have a mileage restriction.
I was kind of baffled, as my friends said they didn't have a restriction. That was the only deciding factor in my decision to choose Grundy.
Does your policy have a mileage restriction?