Reagan, like all of us (hopefully) grew into his views over time. He wasn't always the great sage some people seem to think he was/is. He really thought about things. And like all politicians he was forced to take positions on some subjects that were unexpected. For example, concerning abortion, most people might imagine Reagan always had some set position from early on. He really didn't up until the late 60's (page 380 in the book mentioned above. He said that back then "It was a subject I'd never given much thought to and one upon which I didn't really have an opinion". He said this in 1975 when he also said "An unborn childs property rights are protected by law - it's right to life is not".
There are superficial comparisons of Arnold to Reagan. If Arnold wins (doubtful) only time will tell if his thoughts run towards the depths of someone like Reagan. That would be hard to imagine. Reagan was/is so bright.