Skip any aftermarket service manual intended for Tohatsu/Nissan outboards. They are far too general to be of much use. A clue that you are looking at an aftermarket manual is that they are designating the motors by year. Year of manufacture is irrelevant for servicing a Nissan OB. The Factory manuals are available from any Tohatsu/Nissan dealer, and are what you want. The 2-stroke models are now long obsolete, so Tohatsu has combined the 1- and 2-cylinder models into a single manual, but the original info for your model is there, and is correct for your motor.
Likewise, I always prefer OEM parts to aftermarket "1 size fits all" parts. In the end, they are more reliable and durable, which translates into better overall value. If your parts monger is designating year of manufacture, they are not real OEM parts.
The 40C was available either with external ignition coils, or they could also be integrated into the CD box. Current replacement parts have separate coils, so if you end up needing a CD, you will also need 2 ignition coils. No big deal.