ARP (Address Resolution Protocol) explained

When we see in ARP request packet in the Target hardware address (THA) field 0000.0000.0000 (instead of FFFF.FFFF.FFFF) maybe it is connected with the older broadcast address standard? I have read in the „TCP/IP Illustrated„ written by Kevin R. Fall and W. Richard Stevens in the “Proxy ARP” chapter that „some used an older broadcast address (a host ID of all 0 bits, instead of the current standard of a host ID with all 1 bits)”. I can’t find more information about this older broadcast address standard. Is my conjecture correct?

Link to the quoted sentence:
https://books.google.pl/books?id=X-l9NX3iemAC&pg=PA175&lpg=PA175&dq="older+broadcast+address"&source=bl&ots=Z2djp_J07L&sig=QDrrrD8QEBtPMOI2mx5iwxZSNlY&hl=pl&sa=X&ei=UrCPVMbYD4a9Ubavg5AC&ved=0CCUQ6AEwAQ#v=onepage&q="older%20broadcast%20address"&f=false