This may not be important regarding the radiator support/frame (radiator core?) but in 1954 the horn was attached to the radiator support/frame. I am not sure when this changed but in prior years the horn was mounted on the front of the intake manifold (in those trucks there are no factory holes in the radiator support/frame for mounting horns).

The 1954 radiator support/frame had attachment points for dual horns (I can't remember if they were threaded holes or captive nuts).

Tim