Different Aircraft manufacturers actually integrate the modular G1000 hardware and software into their aircraft. In doing so, each manufacturer has a large amount of control as to what features are actually enabled on their avionics in any particular type or airframe. An example of this is the Cirrus Perspective package which is basically a customized G1000 or the Cessna Nav III package used in Cessna 172S’s.
A good example of an aircraft manufacturer customization related to what you are mentioning is Cessna’s disabling of the split com (COM 1/2) function, COM 3/COM 3 MIC, PA, TEL, and several other buttons in the Cessna 172S Nav III. You can find an online POH to review this info - the POH describes which functions are disabled.
Bottom line: each aircraft manufacturer gets to pick what works in both hardware and software to a certain degree even though the G1000 hardware and base software is the same.