keep in mind that arnold's specialty was his musclemass. therefore, he didnt focus on hitting direct ab shots. but as that pic demonstrates, he clearly has great intercostals, serratus and abdominals. obviously not saying they were the best at the time, as he had serge nubret to contend with, but looking at that picture, u can see the abs are clearly separated and pronounced.
if u dont think they're even good, define good abs.