Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Set
HAIR_SELECTION_TAG_SET
Parameter: Restore
HAIR_SELECTION_TAG_RESTORE
Parameter: Select
HAIR_SELECTION_TAG_SELECT
Parameter: Deselect
HAIR_SELECTION_TAG_DESELECT
Parameter: Lock
HAIR_SELECTION_TAG_LOCK
Parameter: Unlock
HAIR_SELECTION_TAG_UNLOCK
Parameter: Hide
HAIR_SELECTION_TAG_HIDE
Parameter: Show
HAIR_SELECTION_TAG_SHOW