First appearance of Richard Anderson as Oscar Goldman. Despite being featured in the original "Cyborg" novel, the character had been replaced with one named Oliver Spencer (Darren McGavin) in The Six Million Dollar Man (1973) movie. Also, first appearance of Alan Oppenheimer as Dr. Rudy Wells, replacing Martin Balsam.
Some changes to the show's premise were made between The Six Million Dollar Man (1973) movie and the sequel. In the first film, Austin is described in dialogue as being a civilian, but in this film this is changed to him being an Air Force Colonel (and dialogue confirms this version of the character was a Colonel at the time he walked on the moon). As noted above, Oliver Spencer (Darren McGavin) was replaced by Oscar Goldman (Richard Anderson) (a character from the original Cyborg novels) and a new actor plays Dr. Rudy Wells. In addition, the organization, for which Colonel Austin works, is now the OSI, not the OSO.
The exterior submarine shots are from Ice Station Zebra (1968). The SSN number 509 is clearly visible on the conning tower of the submarine.
When he appeared in this feature length pilot, David McCallum was two years away from starring in his own The Invisible Man (1975).