Combination on Mosler Safe

Recently I had acquired a very large Mosler jewelers safe. It measures 32D X 43W X 72H. It is a double door safe with a single interior door. The interior door has a vertical bar that spans the whole length of the door. When turned, that bar will lock the door tightly to the frame. The inside of that door has an offset combination lock, all brass. The lock measures 4 X 3 1/8 X 2. The offset is to the left of the lock and including that it is 6 inches long. Right now the door is open, but the combination is locked. It has a single screw on the far right. I took the screw out and I cannot get the cover off of the lock. It moves slightly to the right, but will not come off. If I can get the cover off and it is not a self changing combination lock, I can find the combination on my own. I'm not a locksmith, I'm in training, but it is not the first safe that I had to find the combination to either. The case cover isn't completely flat. It has a 1 1/8 extension to the cover on the left side of the lock in front of the dial extension gear. There is also a very small extension to the case on the fare right side of the cover next to the cover screw. I just can't seem to figure out how it comes off. Any help in this matter would be greatly appreciated. Thank you.