I think I was fed false info.
Looking around on the web, I found this story about Banfield (Petsmart's Vet):
http://www.canismajor.com/dog/microchp.html#ind
Last month, they put both a 125 KHz and a 134.2 KHz chip into my cat. The paperwork that came with it said the 134.2 cannot be read by most shelters yet. I guess that Congress must've allowed it.