How much of it are you likely to be using?. Obviously, using two of them will give you 16Kbytes - memory is measured in 8 bit bytes, regardless of the bus width.
I wonder what the motherboards companies does with the BIOS for the new computers, are they using 32 bit flash memory?
From what I remember they usually have two flash memory chips on the mother boards - but a lot depends how it's addressed.
The Motorola 68000 series had various chip types, some addressed 8 bit external memory, some 16 bit, and some 32 bit - but all were the same 32 bit processor internally.