Which USB Loader are you using?
I don't know the others very well, but you can see it in USB Loader GX.
Load the loader, go to Settings > Credit
At the top right of the screen you will see which cIOS you are using.
You have the slot number, the name, the version/revision, and the used base.
You can change the IOS to use in the Setting > Loader settins > Main/global (should have a number, 222, 223, 224, 249, 250, etc.)
if you followed a recent (and correct) hack guide, you should have:
Slot 249: d2x cIOS v8 with base IOS 56
Slot 250: d2x cIOS v8 with base IOS 57
You can also just use a homebrew which look at your Wii's content and report what you have.
follow this tutorial : http://gbatemp.net/topic/300279-posting-a-system-check/