No, pinning a device under FASTVP control just prevents future movements by FASTVP. If extents have already been moved by FASTVP, they will stay where they are at the time that you pin the device. If you wish to move extents back to the original tier, you can do so with symmigrate.
Does pinning a device under FAST VP control return extents that were previously moved under FAST VP control
Does pinning a device under FAST VP control return extents that were previously 
moved under FAST VP control