From the American Lock Company website.
Lost Combination
For Assistance Call 1-800-323-4568
It may be possible to obtain you combination. However, for security reasons you will not be given the combination when you call, just the instructions. If there is a key control access to the combination lock or the serial number on the back of your combination padlock starts with 0 (zero)you will have to contact the school or institution from which you purchased or obtained the lock. They may still have the combinations. We do not maintain a file of combinations for these types of combination padlocks.
If your serial # starts with a 5 or a H it may be possible to obtain the combination. Please contact the American Lock Customer Service Department for pricing and details.