The Marysville plant in Ohio has been building Hondas (more specifically the majority of Accords) since 1982. Domestic content is not something new. I don't remember the American/Japanese parts content percentages to have been any different on my 96, than they are on my 06. The engine was sourced from here, and the transmission from Japan on both cars.

As for as engine components, The V6s do use Delphi (supplier of General Motors) for items such as alternators, etc. 4-cylinder Honda engines still use Denso.