There are at least 6 different 3047 Head Versions that we identify for parts. The differences are in the Handles, Bubble Levels, Quick Release Safety Locks and QR Receiver Styling. Not all parts are interchangeable between versions.
The Version 1 has a single screw knob and a tooth to hold the QR Plate in place. As the Versions progressed, A thumb lever was added that uses a cam to old the QR plate. Version 2 does not have a safety lock, while all the later Versions have a safety of several variations.
Some earler Versions used 2 small glass vials that are much smaller than the later Versions 4 thru 6. Later Versions were designed so the larger bubble vials were held in place with a plastic L bracket/casing. The glass vials can be replaced inside the plastic case.
The Versions top has chnaged to a rounded then to a more square styling, they are not all Compatible.
The earliest Versions have hard phenolic handles. As the Versions progressed, the handles were made of rubber, variations in the rubber design are one of the small changes that do not effect the interchangability.
The eariler Versions did not have a safety that would prevent the quick release from being accidentally released. Later Versions were redesigned with the lock. At first a simple flip, and later to a thumb lever. So, later Version parts are not always backwards Compatible.
Mostly due to added features, the shape and style changes over the years. Again, not always Compatible backards.