KGS rank shift?

[daal]

On KGS, I am now 4 dan.

I gained 4 ranks in about 4 months without playing any rated games.

But the important thing is, are you "4d" or "4d?"...

There is a question mark after it, which in my opinion, is appropriate.

The question mark is a symbol which in this context indicates that the system doesn't have enough data to compute your rating accurately. You can read about it here at the bottom of the page: http://www.gokgs.com/help/rmath.html.