GeForce 4 Ti Series Overclocking??

I recently downloaded and added the registry setting that would enable a hidden tab in the advanced video settings named “coolbits.reg”. I have researched on the internet and have asked many friends whether or not you are actually overclocking the video card? All of my resources have stated that the full line of GeForce4Ti series video card have the same chipsets but with lower clock speeds to lower the prices. I have the 4200 card in my machine and have bumped up the speeds to that of a 4600 with no problems. Are the preceding statements true? Is this safe?
Any input would greatly be appreciated!