NOS Mopar Horn Switch 3764664 listed to fit:
74 Plymouth (Fury and variants) and Dodge (Polara, Monaco and variants) with horn ring
75 All models with 3 spoke wheel except Chrysler and Imperial with Tilt/Telescopic
76 All models with partial horn ring, without tuff wheel, without tilt/telescopic.
MAY fit some 77 models as well, but I do not have a book to check.