Yes, it would be incorrect to describe a W boson as a 4th generation charged lepton. The W boson is not a lepton at all but rather a gauge boson, specifically, one of the three gauge bosons that mediate the weak nuclear force. It is responsible for the weak interactions between particles, such as beta decay.
On the other hand, charged leptons are a specific type of elementary particle that includes the electron, muon, and tau particles, along with their corresponding neutrinos. These leptons interact through the electromagnetic and weak forces but not the strong nuclear force.
The existence of a 4th generation of leptons is a hypothetical scenario that has been considered in some extensions of the Standard Model. In such a scenario, there would be additional particles beyond the known three generations of charged leptons and neutrinos. However, there is no experimental evidence supporting the existence of a 4th generation of leptons.
Therefore, it would be inaccurate to describe the W boson as a 4th generation charged lepton since they belong to different categories of particles with distinct properties and roles in the fundamental interactions.