The locks have 2 separate dials that consist of the letters A-K and L-V and several tick marks between each letter. I have included an image of one for clarity.
Your combination consists of 2 letters and 4 numbers, 2 numbers for each letter. For instance G 3/4 and O 3/4. I assume you are supposed to spin each dial until you line up each appropriate tick mark, spin again, move on to the next dial and rinse and repeat. However I haven't had any success yet getting the lock to open. I was wondering if anyone knew precisely what sequence to spin the dials in.
Here is a picture of the type of lock:
http://postimg.org/image/c75qrjxnj/