Originally Posted by drakester09
Why wouldn't it fit?
The differences are not necessarily physical. They may be electrical differences. Why do that? Ask Samsung, but it could be cost control - leaving out parts not used by a specific carrier or country. Or it might be an effort to prevent using a lower priced grey market part in countries where they price a variant part higher.
Whatever the reason Samsung did the same thing for the S3 /S4. For example there are at least three physical S3 layouts. Sprint, the remainder of the NA modules and the international version. The Sprint version is electrically, but not physically interchangeable with the other NA modules. And neither is electrically compatible with the international variants. I have direct experience with this on the S3. I'm told by Samsung parts that the same situation exists for the S5 and have little reason to doubt that this is the case as it is what they have done in the past.