Just remember that, if you install SP2 Beta, wether you remove the watermark or not, it will be neccessary to uninstall it again before you can download the final release. At that time it might also expire and screw your installation so get busy with the backups first.
It is no big deal. Mostly it includes all the updates until the present time, plus some small refinements. Keep in mind, also, that some of those past updates had built in code to cripple pirated copies or, alternatively, you may run into the problem encountered already by one of the members. But of course, no one on this site has such a thing.!