Not necessarily, cos you'l come across teams that play 4231, so their aml/amr's give them width. Other teams might play with 2 in central midfield, but they may have 3 dc's so their width could come from attacking wingbacks which act like wingers. I've just played the World Club Championship final against Santos, they played a 4222 formation. 2dms,2mcs,2stc. I used that run wide with ball shout purely because I'd be one on one with there fullback on many occassion. My inside forward would cut inside, drag the fullback in, then my complete wingback was on his own to pick out a cross in a dangerous area.
The first picture just shows my how far up my fullbacks push up to get a cross in, and how often. Second picture shows the passes we made throughout the match, my widemen made at least 60 passes each! Haha. But if you look for the numbers 20 and 2 down the right hand side, and the numbers 3 and 10 on the left then you'll see where my players recieved the ball and how wide they were. Third one- that we made 17 crosses in the match, most werent successful but we got in the position to keep having a crack. But tbf, we only played 1 striker, Suarez, so I didnt expect many to be successful. Last picture, just the chances we made.