Dave Mugrave mentions that Microsoft Dynamics GP 2013 Service Pack 2 fixes Named Printers and Page Orientation settings not being honoured
Microsoft Dynamics GP 2013 Service Pack 2 fixes Named Printers and Page Orientation settings not being honoured – Developing for Dynamics GP
Install, Upgrade & AdminGP 2013
Archived post from 2013. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.