Are boxed PC retail copies of Skyrim region-locked?

I've heard that all PC copies of Skyrim require Steam activation and am wondering if this is forcing region locking. I want to buy a UK copy of Skyrim and be able to activate/play it in the USA. Can this be done without modifying the game?

I am located in India, and the only way I could purchase the retail edition was a version that is imported. All imported editions of Skyrim in the Indian market available are imported from the UK under license.

But the actual retail box does not display the license, the importer's packaging displays the license number of import.

I also have friends who have purchased Skyrim while on business in the USA. They are able to play Skyrim in India.

But India is not specifically a market where Bethesda officially released the game AFAIK. So do not know if it is considered a "region" in the strict sense. But Steam activation worked for me and my friends.

HTH