The spinlocks are left and right:
Left PN: 986-563-713-03 (Driver's Side)
Right PN: 986-563-714-03 (Passenger Side)
When you drop the spinlock into place it should only fit one way, and you won't be able to thread the bolt if the spinlock is not in the correct position. I thought the Pelican instructions had plenty of detail, check the second picture for the correct fitment.
Porsche Boxster Hardtop Installation Kit - 986 / 987 (1997-08) - Pelican Parts Technical Article