I believe this was the case for the first round of Fluval Spec LEDs. If you get one and the light is defective, Fluval (Hagen) will send you a replacement per their warranty. Most people, including myself, switched out the LED light for something more powerful. I went with the
on light. If neither of these are appealing to you there are quite a myriad of clamp on LED lights on the market too that would work well with the Spec such as the Beamworks Clamp Lamp. Nice white light and plenty of power for growing any plant. Hope that helps!!
As Basil suggested, you shouldn't worry too much about the fixture, as it can be replaced if there's an issue.
Beyond those two additional lighting options, you should have no trouble finding a suitable fixture for your tank if you wish to go with something that isn't stock. You could even go high-tech with fancy LEDs for an affordable price on such a small tank.