Zeppelin is the name of the manufacturer, not a type description, so the recently sighted example is, indeed, a Zeppelin.
The 'N' registered examples were not, being Goodyear GZ-20 series craft.
The term 'Blimp' derives from the early days of airships whereby the Air Ministry divided them into two types; 'A' Rigid, and 'B' Limp, hence 'Blimp'.