On the sixth Gen the Japan's vin start with "J"
Us Vins start with "1" (might hold true for 7th too.)

There is even a Mexican built vin, but I'm too lazy to look it up.
And the Mexican plant only kicks out like 30,000 units so it's rare to ever find one. They usually just supply extra needed engines.

If you have a v6--it's USDM.
If you have a 4 it could be either.

The door jam on one of the doors usually must state the mfg. place of origin, yet to see a car missing this.