You my friend are the lucky owner of a classic, very rare and wonderful sportboat survivor in incredibly fine factory configuration. Congratulations!!! Wow, I mean WOW!
I've never seen one of these in its original condition that has not been restored. I'm sure many of us would love to learn it's history and how it came into your possession.
I can tell you everything appears to be original but cannot say whether the interior vinyl is or not. Other XK-19 owners may know and comment I hope. The engine is the high output (HO) 350FLV rated at 300-320 hp depending upon which year Chris-Craft literature you read. It even appears to be wearing it's factory paint and appliques right down to the painted alloy "Corvette crossed-flags emblem" valve covers.
As you may know, CC was buying the prized, high performance solid-lifter LT-1 engines from General Motors Chevrolet Division used in their Corvette and Camaro Z-28 models of the early '70s, and then CC was marinizing them. The workers at the CC factory just sprayed everything blue including the hoses and those gorgeous alloy valve covers. Here's how a rebuilt one looks w the paint removed from a photo of the original 350FLV in our XK-22:
As for your boat's color scheme, it looks factory correct with the bronze/brown gelcoat portions accented with red stripes. That is the same as used on our 1972 XK-22 albeit your XK-19 gelcoat and stripes are in much better condition than ours which is well worn
Very best of luck with your great find and keep us posted with more photos and updates!