Arnold's father Gustav died in 1972, not in 1974.
First meeting of Arnold Schwarzenegger and James Cameron was not alone in a theater. IT was in a restaurant along with the producers John Daly and Gale Ann Hurd. Also this event took place in 1983 when discussing "The Terminator", while in the movie he met in the mid-1970s, before releasing Pumping Iron (1977).
Arnold's book "Education of a body Builder" came out in 1977, just like the movie "Pumping Iron", not in 1974, as shown in the movie.
When talking to Barbara Arnold said "By the age 30 I will star in my first movie". In the mid 70s, where the scene takes place, Schwarzenegger was already starting in his first movie Hercules in New York (1970). However considering the fact that Schwarzenegger was not proud of this movie this line could be done deliberate to show that Schwarzenegger ignores this movie.