I think they are the same. I have a 64 tagged with the horn ring and a 66 tagged, both look the same. My 65 plymouth horn ring looks different, but it's a 270 ring (not dart or dart gt)and seems to be a full circle instead of a pie shaped horn ring but the wheel is the same as the dart.
I restored mine to the shape and color I wanted my car to be. I used PC7 epoxy and followed a youtube video about notching and grinding the plastic to have a good bonded part. (I bead blasted the plastic first and removed all the rust on the metal steering wheel ring)
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