Yeah, you're probably right.
*disappointed*
Edit: Just to show that there was reason in my madness, and not just me talking out my arse like usual, here's the reason I thought it might be possible. First is the ps2 save structure, second is ps3:
So you see, I was hoping to just copy in the individual saveslot files, not worrying about the SFO and whatnot. No dice though.