So if you're running CM7, then that's not where KB3 radio came from, but rather that's where GRI40 came from. Your i9023 originally came with stock GRI54 and KB3 radio, then when you flashed CM7, it kept the KB3 radio but downgraded your build since CM7 is based on GRI40, not GRI54.
In that case, if you want to be running stock, I would recommend flashing the 2.3.4 OTA full ROM package to your phone. It will give you Android 2.3.4 with the KD1 radio. It works fine on i9023 with KB3 radios. That is the only one of the ROMs that I listed that will work with your phone.
Click the very last link in the original post (under i9023, Android 2.3.3 (GRI54/KB3/KA3). That's the file you want. You can flash that in ClockworkMod and you'll be on stock 2.3.4. Because you're running CM7 right now, you will also need to wipe your data and cache, plus it'd be a good idea to wipe Dalvik cache too.