There is no way to read out the user codes directly. You can determine which user numbers are in use by trying to store a new user code in a user number, If the user number is already in use, it won't let you store a new user code in that user number. The Installer code is user 01 and the master code is user 02. So user 03 is the first available user number. The command to delete a user is:
[MC] + 8 + [user no] +
User numbers are always two digits.
Having said that, somewhere in there is the duress code. Assuming that you know what the duress code is, the only way I know of to find out which user number it is stored under is to enter the duress code to create a silent alarm condition. You can then read out the log with [MC] + #60. The duress entry will have code 121 in it. It will also have the user number. You will have to be on the phone with your alarm company when you do this (Don't use the phone line that the alarm uses) or you will have the police at your door with guns drawn.
The other approach is to delete all of the users, one at a time and then re-enter the duress code at the user number of your choice.
Hopefully you know what the duress code is. Don't post it on here.
The log will also tell you what user number the key fob is using. Hopefully it's the master user number (02).