Possibly, but in that case the post I was replying to makes little sense. There is no "Mystran faith" in the Realms. That's not how polytheism works. Individuals will generally select a particular deity as a Household god (to use the Roman terminology), and keep a holy symbol of that deity around. However, when they wanted something from a god, they would make an offering at the temple of whatever deity had control over the area the they wanted to influence. Or whatever temple was local, if that deity didn't have a temple convenient. So someone who has Mystra as their household god would make an offering of gold at the temple of Walkeen if they wanted a commercial venture to be blessed.
The roll of priests would focus on dressing the temple and the statue of the deity, and performing sacrifices on behalf of petitioners. Some would have a sideline in cryptic divination.
There would be "mystery cults" for those who wanted to delve into the deeper secrets of a deity, so it would be fair to talk about a Cult of Mystra (which would be a part of the FR-polytheism religion). However, the cult may well be completely separate from the temple. What they actually got up to would be very very secret, for insiders only, with levels of initiation providing access to new secrets. They would also be highly localised, so a Cult of Mystra in Cormyr might have a very different set of secrets to a Cult of Mystra in Amn.
As for things specific to Mystra, her historical equivalent as goddess of magic is Hecate (who is not as dark as the early Christians made her out to be).