NHTSA goes by production month of the specific car. e.g. my car was made in February 1998 so February 2023 is when it is legal.
I don't know how they check that, it isn't on the V5C anywhere. Date of first registration is what shows up on the UK paperwork. Which in my case is actually 3/31 since officially the GTSE wasn't supposed to be sold until April but looks like mine jumped the gun a tiny bit or maybe the dealer had ordered up plates for it so it would be ready.
Stick your VIN in one of the parts system decoders like partsouq.com and you should be able to get something like this:
Brand: NISSAN
Name: PRIMERA
Date: 02.1998
Trim color: K - GREY
Frame Color: KV7 - PLATINUM
Model: BBYARUFP11EEAUP
Market: UK-Europe (RHD)
Body Style: SEDAN
Engine: SR20DEH
As far as importation is concerned, you'll need a NHTSA HS-7
Declaration Form HS7 | NHTSA
and a EPA 3520-1
EPA Standard Form 3520-1 – Declaration Form – Importation of Motor Vehicles and Motor Vehicle Engines Subject to Federal Air Pollution Standards | US EPA
And some sort of entry summary for CBP which I don't know what it looks like for boat shipping cause I've always done the import via land border through Canada.
You'll need a customs broker to file these for you. Shouldn't cost more than a few hundred bucks (maybe$350ish) for them to fill out the paperwork. Find someone in Jacksonville All that stuff needs to be in order before the car leaves England.
Also because of port security, you'll need to hire an escort with a TWIC card to get access to the port and get the car.
Whatever you pay for shipping costs and marine insurance, the last part of the journey is the unloading and that costs like a $150 or something which is weird because you don't get a notification until the boat is basically arriving, but then you can't clear customs until you pay it and they make you wire the money which banks charge dumb fees for and are only open during the business hours of the federal reserve bank.
Oh and duty. So because it is a car, it is 3% duty for the first $1000 of the value of the car and 2.5% of the remainder. Which for a P11 isn't going to be much.
When I shipped my car from Southampton, I simply drove it down there cause it was still on taxed UK plates. Because of my travel dates, I had to leave the car on a Sunday morning, hop a train back to London and fly out Monday. But on Sunday the port wasn't open; my shipper guy had arranged for a place I could take it. Basically Southampton is a huge cruise ship terminal as well as port so there are large indoor car parks for all the people out on cruises. I simply valeted the car with them (and gave them a half a bottle of 12 year Lagavulin and told them to watch after my baby) and the shipper came for it later that week. If you do something like that though, know that on the day before the cruise ships leave all the hotels are full so I actually had to stay over in Bournemouth which wouldn't have been a big deal except I arrived without a reservation at like 11:30pm at night with very little fuel in the car, no fuel stations were open, then had to race over to Bournemouth and the hotel lobby for the place that did still have rooms wasn't open 24hrs like a lot of American hotels so the front desk person was just leaving when I arrived on fumes and was like I'm here to check in lol. Anyway I made it. Car has to be empty, and clean, especially the undercarriage. I just ran it through the Tesco touchless car wash a couple times and called it good.