Can the two pins above the AREF and gnd be used for anything?
Yes, they are the SCL/SDA pins. Are also connected to A4/A5 (D18/D19). You can confirm which with a meter.
Or write a sketch that makes one toggle, then the other, and use an LED/resistor to see which is changing. Or a multimeter. Or review the schematic: http://arduino.cc/en/uploads/Main/Arduino_Uno_Rev3-schematic.pdf