doubleofive said:
I believe, yes we are. They have the same face and voice, and are credited as the same actor. The dead giveaway for anyone with doubts is the end of TPM, where Mace asks "but who was destroyed? The master, or the apprentice" and the camera pans to Palpatine.
And the whole cheesy "we will watch your career with great interest!"
Agreed.
Even watching the PT first, you're plainly meant to realize it, at least by the end of TPM.