Any way to recover SNAK from a Dreamcast save file?

I've been trying to search for any information on this and I haven't been able to find anything.

I got a friend who has his original save files from way back in the early 2000s but he doesn't have that dreamcast anymore.

From what I can find, if he had the serial number, he could flash the dreamcast and it would work.

That either means the serial number or it's hash are located in the save file somewhere right?