Thank you for your question and sorry for the late reply.
The truth is, I didn’t know. So, I have taken the time to talk to a shop that rebuilds Bus spindles and is very familiar with our AC Industries disc brake conversion kits. When I called, they were in the process of building a set of flipped spindles. Perfect! I headed over to the shop with a bracket and caliper and was able to do a test fit. It works flawlessly! I can safely say that there is no problem with someone installing this Bus kit on a 1964-1967 with factory spindles that have had the king pins flipped to lower the front suspension.
Thanks for the question and furthering my education!