Gerrie,
Searched for the tables which has the APPROVL, APRVLUSERID or APPRVLDT fields at the company database. Out of all tables, only one table related to GL has these fields, which is SY00500 the batch header / posting definition master table. Once you post the batch, based on the batch type the entry at SY00500 will get deleted.
As the posting approval info is not carried with the posted GL transactions, I doubt you will be able generate the approval report post posting GL Transactions. This is possible in GP2013 as the approval info is carried forward.