Well Newbie, I am by no means an expert. Just a back yard guy that likes the cars and knows a little something about them. It is SO hard to figure the value of a car that can't be seen. That's the first thing. Can you post 20 pictures of this car, or at least a few?
Having no X-Code makes things a touch more difficult, but certainly not impossible. There are MANY other things that can be checked to help determine if this is the real deal. Cause really, that's the first thing. Are you looking at a tribute/clone, or a real 69' Z/28. So you need the VIN, the build date of the car, the build and assembly date of the Engine, Transmission and Rear-End. This can all be acomplished in less than an hour if ya know where to look. I would buy a book written by a fellow Camaro guy, and a figure here on this site, a Mr. Jerry MacNeish. That book will help you along. THEN IF things are starting to come together and the car looks to be the real deal, you can progress. Ask the owner for right of first refusal whilst you do some research. Get the info and list it here as there are many people ( Paul, William, JohnZ, and the list goes on) here that forgot more about most when it comes to Camaro's. There is also a database of many surviving cars, maybe this car is on the list.
Book is called "The Definitive 1969 Camaro Z/28-SS396 Fact Book" Number is ISBN 0-9626399-1-5 Good Luck, I hope it's real!!.....Danny