Did you get any other items with it? Motor control board? Ethernet board? Proto board?
Unfortunately, the Arduino isn't worth much on its own- you need some sort of something to do with it. It's pretty easy to put some LEDs on the IO ports. All you need is to solder a resistor in series with one leg of the LED (330 ohm is a good number) and then plug it into two adjacent ports. Make one high and one low, and the LED will light up.
As for the assembly thing, I doubt Adafruit had anything to do with the assembly. The board was almost certainly assembled by a third party assembly house (and probably purchased by Adafruit, whole hog, from someone else).
If you need LEDs and/or resistors, let me know. I can probably set you up with something- I have lots of that sort of thing.