List<System.Object> geoms = new List<System.Object>();
List<string> guids = new List<string>();

foreach (IGH_Param param in Component.Params.Input[2].Sources)
{
    foreach (Object myObj in param.VolatileData.AllData(false))
    {
        geoms.Add(myObj); // these are the object geometries
        guids.Add(param.InstanceGuid.ToString()); // these are the guids of the parent componenets
    }
}