oil consumption

I am trying to figure out if I should be concerned about my oil consumption. I have an '02 M620 with 2000 miles on it. OIl was changed at 600 mile service, however I have lost about a quart in 1400 miles. I have been told to watch the base gasket for a leak- there is some oil on the motor, but not a significant amount. The only real "leak" I see is from the filler cap. Kinda doubt that I would lose a quart though that though...