The cache is not at the listed coordinates.
At the listed coordinates you will find safe street side parking and a pedestrian gate where you can enter the park. As you enter through the gate turn left and walk along the fence to the nearest tree. In this tree you will find a mailbox attached to the tree. The cache is directly below (not underneath) the mailbox. The mailbox is private property, so please do not search in or on it.
Leaving mail in or at a tree for someone to find is a centuries old practice, like the Post Office Tree in Mossel Bay first used in 1500. This practice has been adopted by geocachers as a preferred place for hiding geocaches.
The stamp is not SWAG, please do not remove