To answer your question: Some international schools are accepted by all 50 state medical boards and there is no distinction made between a US graduate and an IMG. There are some international medical schools that are not acceptable in a few states and there are some schools that are not acceptable in any state. California is pretty much the Gold Standard for accepting or rejecting medical schools. This link is to their list of disapproved schools: http://www.mbc.ca.gov/Applicant_Schools_Unapproved.htm

If your reference to international medical schools is referring to the medical schools located in the Caribbean, all of these schools do their clinical rotations in the US.

Hope this helps.