Missouri instituted a similar "replica" law in Jan. 2005, which is when I purchased my Caterham. I spent hours poring over the regulations, and calling down to the main DMV office in the state capital to ask questions.
I decided that going to a local DMV would be a mistake, as the main office barely knew about the new law. So, I drove 2 hours to the state capital (Jefferson City) and main DMV office to register my Seven.
The law had a similar "replica" component, so I brought one of my books on the history of the Seven/Caterham. Believe I decided to use 1968, but I'm not sure any longer.
When I got to the DMV office, there was only 1 person working, and she seemed like the stereotype of a DMV worker. Unhappy, unsmiling, unpleasant, which made me uneasy.
Just before it was my turn (it was clear the person ahead of me was finishing up), a second worker came back from her break. And she was, in a word, fantastic.
When I said I wanted to register the Caterham under the new Custom Vehicle law, she didn't blink. Just started asking me for the required documentation, which she seemed to know off the top her head. She examined all my paper work, then said she needed to go in the back, although she didn't say why.
I started to fear the worst, then looked down to the end of the counter and noticed a calendar on the wall. The theme appeared to be cars, and the car for that month was a Lotus Elise. I decided that was a good sign.
Which it was. She returned from the back with a set of plates in her hand! She said they were stored in another building, which is why it took so long. She handed me the plates, and number on them was "CV0001" - as in Custom Vehicle 0001. I'm pretty sure I was the first person to register a car under the new law in the state.
Long winded story, but you might want to consider going to the main DMV office for the state for the registration. And hope you find the story encouraging.
Steve