I have to preface a statement with some history about myself.
I bought my 1st 1969 Camaro Z/28 in 1975. Sold it 2 years later, bought another and on and on. From 1983-1997 I was involved with a business selling 1st gen Camaro parts. In those days the cars were plentiful and we parted dozens of them, set up/attended hundreds of swap meets, prowled junk yards from coast to coast, bought and sold an incredible amount of 1st gen Camaro parts during that time. We were small - D & R and Z & Z [to name a few] had many many times more cars & parts than we did. We sold it all: MO & DZ 302 engines, Muncie 4-speeds, '837' alternators, disc brake subframes, 12-bolt axles including 2 BEs, a complete JL8 setup, aluminum intakes including a cross-ram, factory Holley carbs, wheels, glass, sheetmetal including RS conversions and compete bodies supplied by our friends out West. In this time we helped many people restore and unfortunately unwittingly create cars.
This nonsense about claiming a car is an SS, Z/28 or whatever because it has 4-leaf springs, front discs or a 12-bolt has got to stop. We sold all that stuff many times over as did all other Camaro vendors at the time, 23 years ago. While certain characteristcs may have validity such a Z/28 without a Muncie speedo cable routing anything else can be and has been added. The famous '69 LH tailpipe plate takes about a minute to remove intact from a parts car and has been reproduced. And I grabbed many of the meaningless rear brakeline valves in junkyards. Body tags? Don't make me laugh. Those were being swapped 25 years ago. A few years ago I was visiting another vendor who showed me literally hundreds of them in an old toolbox.
The only way you can be certain of a cars' pedigree is genuine factory paperwork or irrefutable VIN-stamped drivetrain componentry.