...yes they do.Ability Score Increases: This is an example of Rule 2. Monsters gain most of what you gain from your Hit Dice, but they don't gain ability score increases every four levels like you do.
When backwards-extrapolating a monster's base ability score modifiers, you subtract one from its highest ability score for every four hit dice it has. Once hit dice reach zero, subtract 10 (if even) or 11 (if odd) from the creature's remaining ability scores. The resultant numbers are the creature's racial ability modifiers.
While there is a table that can be used to determine ability scores for racial modifiers when they are less than 10, the table's primary function is to ensure that a score never drops below 1 (or 3, in the case of Intelligence), and following the regular process with some sense will result in appropriate ability scores.Feat Acquisition and Ability Score Increases
A monsterís total Hit Dice, not its ECL, govern its acquisition of feats and ability score increases.
Also note that creatures that include the following line
would subtract the given value, rather than 10 or 11.The orc warrior presented here had the following ability scores before racial adjustments: Str 13, Dex 11, Con 12, Int 10, Wis 9, Cha 8.