Surprise 2.4 P4 at 3.6Ghz

[swinada]

I just bought this chip because it is the least expensive of the P4's. PENTIUM 4 2.4A GHZ 533MHZ FSB 1MB L2 CACHE
I also read the review that said it can be OC'd with stockcooling to 3.7Ghz.
So I bought a new board (Asus P4S800) and a new HDD, put the thing together and started it up. First nothing happend the FAns came on but no beep or picture. SO I rebooted again, this time it worked and I got a message saying that the first time there was an error because of wrong CPU speed. I went in to the BIOS and checked my CPU. It shows as 3.6 Ghz. I tought this chip is locked, but it gives me the option in the BIOS of 3.6 or 2.4.
Is this normal or am I just lucky???
I will run some tests after WIN install and see if it is stable at 3.6Ghz.