No, this is incorrect. I bought two 3" silvers they fought constantly. I had to seperate them and tried on numerous occassions to put them togehter and they would always fight no matter what. Eventually I ended up selling one of them at about 8".
I had a deal with my LFS for some stuff I did for them. Had X4 2in aro's together in the 180 tank I took them str8 home from the delivery truck they never even went inside the fish store. 1st week had to take one back for fighting. 2 weeks later one was killed by the other 2. Then 2 months later the last 2 remaining started fighting had to take one back to the store. I think it is mostly just luck if they get along