After you import a goods receipt, the in-stock quantity is updated in the warehouse.
In addition, if perpetual inventory is in use, a journal entry is posted that debits the inventory account and credits an offsetting account. These accounts are defaulted from the G/L account determination. A best practice is to change the offsetting account to an opening balances account so there is no effect on other general ledger accounts.
You can specify the opening balances account in the IGN1 template.