Yeah they can do assists but I've never seen a fullback that can actually score consistently, most of them are long-shots that don't even come close (even if I give them PPM to pass rather than shoot). In fact my right fullback has 1 goal in 127 games. I think DC are more accustomed to scoring, I've got one with 23 in 189 games, and another with 30 in 302.. so like once every 10 games . It's better than my fullbacks for sure.
A few years ago, I had Riise and D.Alves as wing backs on my Liverpool team. They both got 15-20 a season. This was back when we had arrows and stuff that could curve, and they were set to run to the corners of the box all the time.
My fullbacks get a LOAD of assists, but generally only score from set pieces or long range. Maybe something that needs a small look in the match engine, as there are some full-backs who do like to cut into the box and shoot relatively often.
It seems that full-backs only overlap on the outside and tend to stay really wide, while in real life there are a few that like to make runs into the channel, don't see that so much in the game.
My fullbacks usually come up with two or three goals apiece throughout the season, but there's no rhyme or reason to it and it has little to do with tactics. I've got a couple that are pretty good set piece takers, though, and that seems to be the easiest way to get them to score.
The best result I got in terms of consistency was a right footed fullback on the left side who could dribble well; every once in awhile he'd cut in and rip a nice shot if he was on attacking duty.
I once had a Dutch left back whom I signed for Man Utd. When I had him at Den Bosch he barely got on the score sheet but at Man Utd he started hitting freekicks and taking penalties....think he ended up with 8 one year - which in my books is A OK.
Had a Welsh regen LB in FM09 with 20 free kicks and 18 in long shots and technique. He was banging in a free every 2nd game. Literally. Think he ended the season on 28 goals (17 league). Haven't seen the like since. Also had Michael Turner put away 11 goals in a season for my Forest save (7 corners 4 penalties), including a winning 91st min LC final penalty.
I've got Diego Renan playing left back for me, his most prolific season he got about 8, all from cutting inside and leathering it towards goal. (Worth noting however that 9 out of 10 times he'd blast it over the bar)