Yes, this is the final version of Windows XP SP2.
RTM means release to manufacturing, chances are the "final" won't be any different, as RTM's are preinstalled on new systems etc..
Following an RTM is an RTW, Release to Web(site) which means the general public may go about downloading the product, in this case, SP2.
On tuesday (not sure if it's this or next week) SP2 will be available via Windows Update this is different from RTW in that users with Windows XP and auto-update enabled will automatically download SP2 and SP2 is avilable on windowsupdate.microsoft.com.
To tell if the SP2 you have downloaded is authentic check the following:
1) Download Windows XP SP2
2) Download an MD5 hash checking program:
MD5
fsum
MD5 - digestIT 2004
3) Check the file hash, make sure it matches one of these:
Correct MD5 Hashes
English:
RTW: 59a98f181fe383907e520a391d75b5a7
MSDN: 94276421fa963122a4e434d3b14fdc01
German:
RTW: 2fa1439dd7425848ba187213f9b9949f
4) Check that your build is Digitally Signed, if it isn't chances are it isn't authentic, however if I recall correctly, the MSDN release isn't digitally signed..
To check for if your version of SP2 is Digitally Signed do the following:
a) Right click the Windows XP SP2 file you downloaded
b) Click on Properties
c) Click on the Digital Signatures tab
If there isn't anything in there with Microsoft Corporation in it then your version of SP2 hasn't been digitally signed, meaning it could possibly be a fake.
5) Check the build number
To check the build number, do the following:
a) Open Explorer or My Computer
b) Click on Help
c) Click on About Windows
The about window should have the following in it:
Version 5.1 (Build 2600.xpsp_sp2_rtm.040803-2158
ervice Pack 2)
I'm only telling you guys this because there are a lot of different builds out there on the internet, just be careful with what you download :\ some of the builds out there contain viruses/trojans..