Duckin

So, Benelli’s fully rifled slug barrel which was originally made for the SBE will fit the SBE II. With that in mind I compared my SBE to an SBE II. It seem that the receiver is the same in both, as is suggested by the slug barrel fitting both. So I am guessing that Benelli redesigned the trigger guard, barrel, forearm, etc.. but kept the old receiver. If this were true one could modify a SBE into an SBE II if one had the relevant parts? I realize that this would not be cost effective as a new SBE II is probably cheaper than all mentioned parts but would like to know if this is correct.