That is the monster's attack bonus, yes - it is the complete bonus for the attack, you don't also add the strength modifier or anything.
The Reading Creature Statistics section from the bestiary gives some additional detail on what each part of a creature's entry means.
Thank you for the quick response and the additional information. I have not dug into the Bestiary yet as I am still making my way through the core rulebook. I am trying to get through everything quickly as I have a very excited son and daughter that are ready to play!