HM Bosses in Old Ascalon

This has been bugging me for awhile, I have been farming in Hard Mode Old Ascalon, fighting and killing Hulking Stone Elementals using a Riposte Build i found on Guildwiki. But as much as I have been doing it, I havn't yet got a Elite Tome from the Locked Chests i find, or from the Elementalist and Warrior Boss that i often run into.

My question is: Do Elite Tomes drop it areas like Old Ascalon?

From my own experiences it seems to be exceptionally rare, although not impossible, for bosses without an Elite Skill to drop an Elite Tome.

I used to grind farm the Charr at the beginning of the Nolani Academy mission in HM where there's a stampede of Charr and one boss. Out of the hundreds of times I repeated that process I only ever got one Elite Tome.

So, its rare, but not impossible? Great, thanks