Well, the repeated copies of the same ROM don't repeat inside the size of the ROM chips -- they are repetitions of the entire ROM contents. They do that because some of the address pins are left unconnected, depending on how big the installed ROM chips are.

In this case, it means that they definitely left earlier IIci startup code somewhere in the ROM. In fact, they went so far as to leave in the old *synthesized* startup sound code for II series Macs (along with the sampled startup chime that the 650 uses).

http://mess.redump.net/mess:driver_info:mac_technical_notes

The above list seems to show on some II series Macs, a few of the VIA data register bits will identify the model.