IMO, the meeting Kim had with the Prime Minister was to discuss the steps (including changes in legislation and related security measures) to take for the insertion of the GM silkworms in the VN industry...but obviously, Kim could disclose those aspects of the discussion.
I also think that considering the relation of trust established between VN and the US and the importance of the economic exchanges between the two (specially on the silk industry), VN will rely on the US to define its parameters.