Greg,
No, I think you have the pins wrong when converting from a AT28C64.
Take a look at the pin out of the AT28C64:
Now to convert this to a 2732:
Pin 24 on the 2732 (VCC) is pin 26 on the AT28C64B. So when the 4K rom is selected on the motherboard you need to supply pin 28 on the AT28C64B...