Welcome to the forum Hyusufi! I don't know if any of this helps, but here we go.
Your suspension fork cap appears slightly different from mine, probably a different model, but should be similar. When you remove the center screw and cap, the underside of the cap should have a hexagonal depression that fits over a hexagonal cam protruding from the top of the shock. I believe all of these caps are of a similar design.
Now, while I can not find an exact "Mozo" replacement, a third party cap may work just as well, such as for Fox, RockShox , Suntour, etc.
or
You will need to compare what you have to those different models . Look for "suspension fork lockout lever" on some the bicycle parts sites such as JensonUSA, bikeparts,com, WorldwideCyclery as example or your LBS.
You mention that the fork appears to still be working. In lockout the fork should be very stiff, difficult to compress, when open you should be able to push the fork down and see it rebound like . . . well . . a shock or a spring. The lever is simply opening or closing a tiny valve in the shock allowing oil past a damper and piston in the shock. This is the compression lockout on that shock strut side of the fork. The other shock strut contains the schrader valve and air cylinder. When the shock compresses faster, a greater volume of fluid has to flow through the tiny valve so more pressure is required to force the fluid through. This increases the stiffness of the suspension because the pressure resists the motion of the shock.
Now, in my observation, most people either leave the fork open or in lockout, and hardy ever touch it, a kind of "set it and forget it". It really depends on your riding style. If you are a very active mountain biker, you would probably use it much more often than other people.
For myself, as long as it is still working, it is a cosmetic damage and I could live with it. The replacement cap may cost $20 to $25.
