Yes; it does.
All will 'sleep' until the last trumpet sounds. Then the DEAD IN CHRIST will rise...
I see no reason for the soul of Mary not to be in heaven.
While I don't see any reason for it TO be.
The feast at the wedding in Cana testifies that Mary believed in Jesus, for it was she who told them to do whatever he said, knowing and believing that He was about to astonish them. Take care when you discuss Mary the Mother of Jesus. Science tells us that a Mother carries cells from her children who have gestated in her womb ... and these cells are there for the rest of her life barring a radical hysterectomy.
Considering that Mary saw her own need for a savior, that would indicate that she recognized that salvation was not through the Law, but by faith. I would then think that it would be reasonable to conclude that she is in heaven.
If, however, you are speaking in terms of where souls go before being reunited with their bodies, Jesus went into Paradise and opened it for access to heaven.