Yes, I have one. I believe that these were "example" slabs of the latest type of PCGS slab when these replaced the old rattlers. They were supposed to demonstrate the new style of slab. Maybe some expert knows the history of these. But it's a real slab. Interesting they would use Kennedys for this. I guess these half dollars were so available that it was used as an example.
These aren't sample slabs and they did not replace the rattler slab. These were produced in 2007 and the rattler slabs were stopped in 1989. They are a short run of slabs likely produced for a large distributor such as Home Shopping Network.