You are right about the rotary bodywork having a cut out but it was originally meant for rotary valve 100cc FA engines which have the carb on the side of the engines because the rotary valve spins with the crankshaft.
Reed bodywork is for reed valve engines like the Rotax Max or ICA engines that have the carb out the front of the engine in front of the reed cage which is behind that rubber boot that your carb is attached to.
There are two main makers of bodywork, KG and Righetti Ridolfi. Like most things in karting both of them are Italian manufacturers.
The CRG in your photo has a KG nose cone which is the style that I prefer. The RR bodywork looks the same to untrained (not tarty) eye but there are differences in the overall profile.
I am sure you have seen some of the new bodywork on 2003 and 2004 model karts that are going round in some of the classes. My kart is a 2002 CRG and it is illegal to race with the 2003/4 bodywork on it.
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