Is this character LCD defective?

I recently bought a 20x4 character LCD from SparkFun (LCD-00256). I hooked up power (5V) and GND to the LCD without my microcontroller connected just to see if the contrast would work. I used a 10K pot like I've done before with graphic LCDs but I've never use a char LCD.

Problem is, the contrast pot only seems to control the 2nd and 4th lines, not the 1st and 3rd. Is the LCD defective? I'm waiting for SparkFun to reply to my email about it.

Thanks.

The display should be fine. The missing lines are activated/selected by the proper initialization program from the microcontroller.
Miguel