I bought Barth in Canada before 9/11. It was US build and had all the stickers.
Canadians wave me thru, while US officer shout from the window "How many Mexicans you hid there?"
When I shook my head that none, he waved me thru. I had no licence plate as seller had to keep it in Canada.
Later in US I had to go to US customs for inspection, but I live close to Oakland port, so that was not an issue.
Don't know if the law changed since then, but if you want to get good price in US, get that inspection done ahead of time.