Yes you should be able to, as the GM is the same build that goes out to the public. If you are on a beta of 7.0 and expect to get to 7.1 it will probably fail, as the 7.0 betas expire, and GM's don't expire.
Yes you should be able to, as the GM is the same build that goes out to the public. If you are on a beta of 7.0 and expect to get to 7.1 it will probably fail, as the 7.0 betas expire, and GM's don't expire.
To further clarify. The GM, or GoldMaster, by definition is the load that is given to the factories to load into the flash memory of all the iPhones going out to consumers for release day...
If the build number of the GM version is the same as the public version (which it almost always is), there will be nothing to update to. When Apple releases an update, there will be a new build number, so whenever there's a build number change, you'll be prompted to update.