Yeap you got right. But I think is better if tune your guitar in open E so you can "slide" the chorus chords. That would me it sound more blues stylish.
Playing it in normal key I found another way to play de riff so you can optionally use de E chord. This way:
e|-------------------------------------------------- --------
B|-------------(0)--(0)-(0)-(0)-(0)-(0)-(0)------- ----------
G|-2b4-2-0-----(1)---2---1---2---1---2---1------ ------------
D|---------2----2---(2)-(2)-(2)-(2)-(2)-(2)--- --------------
A|-----------4-(2)--(2)-(2)-(2)-(2)-(2)-(2)- -------------…
