I checked a third time to be sure and well you can bash my head, virtually
.
From a warrior game, I drop all scrolls to be sure. And the warrior does the same dialog choices but at end doesn't receive 2 scrolls.
I apologize.
EDIT: The only point is my savegame come all from the 1.64 version but the more recent that comes from 1.7. Gamebanshee walkthrough mentions two scrolls reward, but I suspect this is wrong even with savegame from 1.7. It's quite possible that this is only for mage.