I don't have the telephone umber off hand, but the Chitown office that handles city firearms registrations will know for sure.
There is no reason to hesitate to call them (Unlike, say, the same office in NYC that is staffed by a bunch of anti-gun retards where you will be spoken to as if you were a criminal because you need to know how to register a firearm in the city)
The Officer I spoke with in the Chicago office was 100% pro-rights of honest people and sounded just as disgusted with the moronic City firearms laws as they pertain to honest citizens as you or I are with them. But in the end, he was the one who had to deliver the bad news about how crappy the gun situation is in the city limits. He even talked about certain personal gun related things he has wanted to buy but no one will ship to a Chicago address, so it's a PITA even for him as LE.
Yes, LE are able to posess handguns in the city proper but I don't know if this is restricted to handguns that are used in an official capacity or if they're allowed handguns beyond this. He did say that all handguns are restricted to LE "and only LE can register one".
But look on the bright side.
Since Chicago has outlawed handguns, that means there is no handgun crime there!