How to check that GR for TAS had been done

Hi,

User created a Sales order for 3rd party using TAS.

Purchase requisition was created and followed by Purchase order.

Order was released and GR was done.

MY question,

a.     Where can I check from the SD tables that the GR status had been updated?

        can I get the information from VBUK / VBAK ?

I am trying to draft a report to display document due for billing. In this case, I only want it to be shown only when GR was done.

Anyone can assist?

Thanks