The compression ratio of a '68 302 could be anywhere form 8.7 to 10.0:1 depending upon what version you have. But if you are doing the compression test correctly as described above, a reading in Sacramento of 95 psi for any of them means something is wrong and the engine needs work. If someone claims it has been re-built - don't walk, run.
As you go up in elevation the compression psi would be lower. But for 95 to be an OK number you would need to be sitting at an elevation of around 10,000 feet above sea level.