I don't think so, no.
Possession like on Supernatural has never existed on BtVS. Just like the vampires and werewolves are different on both shows, each show has its mythology when it comes to the monsters they have in common. I never saw any similarities.
Don't forget, Glory is trapped within Ben, it's HIS body she's using. Ben was specifically created to be Glory's prison when she was exiled from her home dimension. Ben is Glory. But she learned how to take over his body and assert herself, and she takes control of Ben's body as and when she wants to. We see that shift more than once, especially in 'Weight of the World' and they're switching back and forth over who has control of the body. It's actually a great scene, really well filmed and executed. They really hammer home the point of it being two people in one body without resorting to bad CGI.
I just always assumed that it was the female form of Ben. Glory is a powerful God, she has power beyond imagination and her true form is, apparently, female. It just made sense to me that, when Glory's mind was in the possession of Ben's body, the body changed and manifested to represent Glory's true form as much as possible.
