Hi Liam,
Yes the P1 is basically just an oil change and inspection.
Service schedule here for the 350z: http://www.350z-uk.com/topic/31110-service-schedule-for-a-350z/
Not sure what year your Zed is but they are older cars so I wouldn't worry too much about it damaging resale values especially with just an oil change. If it was me I'd write it in the appropriate section the mileage, date it, sign it with what I've done and a note of any invoice numbers for the oil filter, sump plug & oil.