Not really. Arnold in his early years had an above average chest. It was only through a lot of hard work that Arnold greatly improved his olympia winning chest.
The below picture is quite interesting, it probably is from June 1966.
It is a testament to Arnold's significant muscle gain leading up to his first Mr. Universe competition. From a modest size chest to a massive chest and impressive overall size at his debut, Mr. Universe in September 1966, it's conceivable that Arnold put on around 20 pounds of muscle within a 3-4 month period. He probably upped the dose into the competition.
