All Operating Systems (OSes) come out from the same source...which is RIM....it doesn't matter for example if you download OS 126.96.36.1996 from Etisalat or from Vodafone, they are 100% the same since the versions are the same.
The vendor file contains carrier specific information so if you try installing the Vodafone 188.8.131.526 for example, Loader.exe will detect that the carrier info does not match your phone so it will simply not install, just delete the file, and you can install perfectly.
Here is how it works...
RIM releases an OS and sends it to many carriers worldwide...
Because carriers are very busy usually having tons of issues from other phones as well and testing in progress, they simply don't have the time to update their site each and every time RIM sends them a new OS. So they may skip many updates. The good thing is, since RIM sends these OSes to various carriers, one or two of them usually do the testing, and once approved, they publish it as "Official" and put it on their site. So you can safely install any OS from any carrier as long as it was for your specific device model.
Same thing with the leaks,
RIM Releases an OS to many diff. carriers. then carriers start testing the OS, but not of them have the time to do all tests on each and every OS so sometimes they skip testing one of these OSes, at this point, the leak happens, is someone employee from carriers, leaks it out even though it wasn't tested
But that makes it no different when it becomes official? It just means that a particular carrier has adopted the OS and released it on their site.
So they are both the exact same with the exact same CODs and file versions