A simple observation will be that such countries do not have a dedicated office to handle dangerous goods or radioactive material.
It does not mean they do not import or export dangerous goods. Dangerous goods and radioactive material are nowadays vital to everyday life. People cannot live without automobile gasoline, mobile telephones and radiopharmaceuticals for medical use..
The other possibility is that the person in charge of that country has not properly advised IATA of any changes. Without new information, IATA will simply duplicate information from the previous edition. The State must make the revision and if such is not done, the information in the book remain stale..
If you wish to secure latest information, the best is to approach the Commercial Attache of that country at their embassy or consulate.