[HAM] hammond cabinet lock

[Borecky]

Hi, Can anyone advise me on how to remove the lock and key assembly from 
a hammond B3. I have the flat key style.
I've removed the two screws in the side plate, but it seems interlocked 
with the round key hole ring.
The keyhole ring also sits about a sixteenth of an inch above the 
cabinet. How do I make it sit flush?
Any help would be appreciated.
Thanks a bunch!