Some games can be tricky. For example the 1st print may have nothing and the 2nd print may have a poster. Or the 1st print may have one poster and the 2nd print another. So yeah, it requires patience.
I highly recommended Wiz's NES Game Contents list as a starting point. It's a list of sealed games that were opened. It contains all the contents that came with the game and since the games were sealed, it's 100% CIB.
https://gamefaqs.gamespot.com/nes...
NG III should have:
-Manual
-Danger Do Not Open NP Insert
-Gray Epilepsy Warning Sheet
-Tecmo Games...HARD TO BEAT! Insert
- Flat Black Dust Sleeve.
DD II should have:
-Manual
-One of the 8 1989 NP inserts
-Poster
-Registration Card
-Flat Black Dust Sleeve