Partly. Also partly just posting controversial comments. But while method acting is one way to roleplaying, and in fact a version of it is one of my favorite ways to do it, it's not what makes it roleplaying.
I generally enjoy the 'you + PCs motivations' method of roleplaying. In other words, know where your PCs personality is distinct from you, what their motivations are, when making decisions relevant to it. But otherwise just make decisions you feel best.
At its core, roleplaying is the player making decisions for the fictional character in the fictional environment. That's a form of playing the role, but it does not require a fictional personality. While I'm not a huge fan of it, a player is still roleplaying if they are merely playing their own personality with different capabilities in the fictional environment. (Most often called an 'player avatar' or the like.) As long as they are making decisions for their PC in the fictional environment, they are still roleplaying.At it's core roleplaying is literally what the name describes, playing a role. At least to me this is much more about how the character talks than how they fight, and I very much enjoy using method acting in this (although I know people who don't and are just as good or better roleplayers than I am). I'm a firm believer in more talk before the have starts, I'm much more likely to try and run a mystery campaign than an explorative one, and highly likely to include at least primitive firearms.