The problem with the non-original carburetor is that it is very hard to do the setting. The thread of the air screw is not made precisely as needed. Even if you manage to set it to good setup, the thread tends to adjust itself to improper position.
This carburetor doesn’t have that problem. It is good to go. And if you notice, the slide inside the carburetor is in black colour.
VM26 means the carburetor size is 26mm.