I never considered a metal covered pickup as the definition of a lipstick pickup, and that includes the telecaster neck pickup. Telecaster pickups have a base bobbin with coiled wire, magnetic poles, and a metal cover on top. A real lipstick pickup is a bar magnet and wire coil directly wound on it with the whole shebang fully contained inside a metal tube. It is a fundamentally different design, and that likely drives the sound differences.