Is my cd-key a legit one?

[potissimus]

Hey there.

First off, let me begin by saying that I am NOT asking for a serial.

A friend of mine had preordered SWOWWII and then changed his mind about getting it. I decided to buy it from him.

The problem with this is that he claims that he (already) lost the cd case, but had written the cdkey on a sheet of paper and gave it to me.

So my question is: Are there certain numbers that start legit cdkeys (similar to that of BF1942 and RtR) to make sure he gave me a legit cdkey?