Hi  The answer is no...  
We are allowed to use the database anyway. It could be outdated. 
Most of the data is 2 years old.
After some years the is an new survey by the government. 
If you select a traffic_sign info will tell you the last survey.

The only database we use for import is buildings and addressnodes.
Otherbulk imports must be discussed at the Dutch forum.

The traffic_signs are also tagged in the roads for routing purpose .  That is not the fact in the traffic_sign database.  

Greetz,
eggie