Aplologies for delay.
You can download the Unity Push Sample. I have added an API by which you can track that the application is opened using Notification click or not.
Here are steps you need to do in your project.
Do replace app42pushservice.jar file in Assets/plugins/Android folder.
Also apdate the App42Push.cs file with the sample application, new API are added in this file.
Here are the API added in App42Push.cs file to get the status of Notification click.
API used to track whether Notification is clicked or Not. It returns true if clicked else return false.
Using the second API you can resetNotification click status.
I have also added a default Android Activity in plugin jar file so you need to add following Activity in your AndroidManifest.xml file.
Let me know if any query is concern.