of course they were - but with our current CIA, we can never "confirm" anything. the AQ Khan network, the Pak program, came from China initially. and they have been shopping that technology package to NK, Libya (since abandoned), Iraq, and Iran. But the issue always come down to being able to enrich enough material to make the core.
-- the AQ Khan network, the Pak program, came from China initially.--
Courtesy of BJ Klinton loosening export controls to China.