If we go to the possession neutral statistics, which is the correct way to look at these team stats. During the 82 game haul:
The Lakers were the 3rd best offense in the league, the Celtics were 10th. The Lakers were 2.9 points better than Boston per 100 possessions.
The Celtics were the best defense in the league, the Lakers were a solid 6th. The Celtics were 2.6 points better than THE SECOND BEST DEFENSE, and a full 6.6 points better than LA.
In the playoffs, in a full Gasol universe:
Lakers the 3rd best offense among the 16, Celtics were 7th ... Lakers were 3.8 points a game better
Celtics the top defense in the postseason, Lakers 5th ... 3.7 points separate them
The teams have been remarkably similar in other places ... both teams pass a lot, and commit more turnovers than you'd want, they shoot the ball very efficiently, they don't really rebound particularly well especially on the defensive end ... it is very close