Yes, you can use WE# low and OE# high for write cycle in 1Mb part also, infact in all density parts.
The purpose of providing an OE# low and WE# Low waveform for write cycle was to highlight the fact that even if the user disables the output (by driving OE# high) the write is still going to happen in the memory. It only signifies that WE# pin needs to be low for a write to happen irrespective of the status of OE#. You can check this in the truth table also provided in the datasheet.
Thanks and Regards,