I think this is right:
gl1500 - goldwing - same basic motor, but very different from a Valkyrie in most ways. Even
the motor, which is probably the most similar thing, differs by having only two
carburetors and a different cam who knows what all else... a bearing here,
a rotor there, the alternator interchanges if you put it on upside down and
backwards (or something like that

)
gl1500c - Valkyrie Standard
gl1500ct - Valkyrie Tourer
gl1500cf - Valkyrie Interstate
-Mike