Screenshot time.
This was her inventory when I logged in a few minutes ago:
[You must be logged in to view images. Log in or Register.]
Then I killed her:
[You must be logged in to view images. Log in or Register.]
Then she respawned and checked her inventory, no gate potions:
[You must be logged in to view images. Log in or Register.]
As you can see, they keep their entire inventory, including things sold to them (raw hide armor, fine steel weapons, etc). Even after death and respawning.
I killed Torlig Mudel and his behavior was exactly the same.