Exactly. He certainly read in preparation for Steve in the first film, to catch the essence of the character, but he didn't need to read everything if he knows it's different. He needs to focus on what's in the script. What he said is what happens in the movies. Blame the Russos and writers for having changed the characters, but not him.
Some fans of Emily are upset with him. I saw someone sends message to him on twitter asking him to respect Emily, others think he hates her, thats why she is not in Cap-side tour. I think she is in tour because Scarlett and Elizabeth are busy.