Yes, as AFAIK Netuno and Netuno C are names of models built by Beep but "Netuno" isn't part of the brand name.
Hmm, this one is jolly confusing as some documents suggest Netuno is part of the marque name, and others don’t, but either way, I think we are both on the right lines. As an interesting aside, this puzzle ‘1903’ model from 1991 was one of three Labate derivatives named after the Company’s founder, Claudio Labate, with the Labate 1922 using a Chevrolette Opala engine, and the Labate 1934 model a Ford V8 motor.