How to retrieve identifier of a selected 3D object?

In my project I want to do the following things:
I have a SketchUp skp file with many 3D objects, each with an ID. Then I want to use Unity to build an iOS app to display these objects. When user selects an object, I want to display information related to this object. To achieve this, I need to know the ID of the selected object. Is this possible? I’m not sure if the ID mappings in skp file is still kept and retrievable in the Unity scripts.

Can somebody help?