Yes, you can create a bus object in Simulink that includes a 16-bit bitfield element.
% Create a bus object
busObject = Simulink.Bus;
% Create bus elements
element1 = Simulink.BusElement;
element1.Name = 'BitField';
element1.DataType = 'uint16';
% Add elements to the bus
busObject.Elements = element1;
% Save bus object to base workspace
assignin('base', 'myBus', busObject);