Space for 790 FS flash on 780 board?

I realized a 780 with a 790 rom is not quite the same machine, namely the missing 14mb flash filestore.

Did NEC leave space on he 780 board to add the filestore flash rom? I doubt it but thought I'd ask.

The g/f is "not amused" about this issue because she's too lazy to back up and relies on her 565 fs to save her @ss when things go wrong. I can't get it into her head saving to her cf is as reliable as saving to the filestore.