NCOA Session ID

I'm trying to do an NCOA update that was done through a vendor besides MBS, so we do not have a session ID from the original export. If I want to use the NCOA Processing Utility, what should I use for a session ID in my import file? Should I simply use a random number, and will that allow the import and update to work properly? Does that number come from t_next_id?

thanks,

Brian