The previous posters have noted most of the differences between a 400 - which is a cool car by itself - and the Caribbean. The Caribbean had the "hood scoops" as noted, different side sculpting, and "should have" a 2x4 engine. Packard experts can correct me on that one.
I usually can't stand white, but this looks nice, with that orange/red section which is carried over to the interior. 15 to 25 years ago, during the golden age of collecting and about 200,000 more Packard fans that have since deceased - this would yield $35,000 and go to a Packard specific collection. Now? I am not sure.
As I have said before, folks need to understand that every 1956 Packard was made knowing it was the end. Sometimes for employees that had been there 45 years, dating back to the teens, and many workers who came on in the depression with the 110's and 120's.
So with this car you likely have a very personal interaction between the workers who knew they were done, assembling with a care a car that is an artifact and has survived all these years, to be enjoyed by the next owner, turning the key to the right, firing up the last Packard, and enjoying life at a pace more reminiscent of 1956 then 2024.