check point to derive for which GL Period the transaction need to be posted

Hi Team,

Need some information on how the GL period will be derived for
Inventory transactions,

Per exmaple,

There is sales order issue transaction happed on 31-DEC-2014 6 PM EST. and the Create Accounting Ran on 1-JAN-2015 2 AM EST.

Whether this transaction will be posted to GL in DEC-2014 period or JAN-2015 period.

Note:- on 31st DEC both GL Periods (DEC-2014 & JAN-2015) opened

Kindly let me know where is the check point to derive for which GL Period the transaction need to be posted

Reply is highly appreciated

Thanks,
Krishna