The behaviour looks somewhat changed. I now use Mx 7.13 and may view the createdDate as long as I have access to the object, that means: some access is granted, like creating / deleting / read an attribute.
It is currently not possible to expose these system attributes to users which don't have the module role System.Administrator
Upvote this idea to get it on the Feature Request agenda of Mendix
1 - open the entity, access rules, give read access to the module role.
2 - check whether your user role is checked for the module role of 1
You could make two attributes in the entity of which you want to display these values to achieve this: Changed_Date, Changed_By for example. When the object gets changed you write the [%CurrentDate%] into the Changed Date and retrieve the name of the user who changes is and write it into Changed by.