I really wouldn't say that, they are comparable but not the same, although you cannot argue with the results of a guy like Alpha that does them.
However, modern bodybuilders get far more shredded these days utilizing the bike and treadmill than the oldschool guys did, though some argue that is just a matter of drugs and the greater demand for super conditioning that wasn't a priority in judging back then.
In general, golden age bodybuilders thought of contest training as the time to bring the most separation and detail into a muscle while also burning off the fat around it by doing supersets and high rep/volume training with little rest time. They did not think in terms of "burning calories" except that they cut out carbs to be as low as they could handle.
Many people today would say that they were idiots for thinking this, though they achieved legendary physiques by doing so, and it is especially impressive considering the new information surfacing about spot reduction now. Burning extra calories through long workouts, and repeatedly getting tremendous circulation and heat into every part of their bodies could absolutely have an effective fat burning effect in my opinion.