We did this all before for you. So review these links and post up any additional questions raised or points needing clarification.
But based on what you just wrote here a white cab roof (conventional two-tone) on a 525 yellow truck is correct and a stand alone option. However it included the divider molding (D99) from the factory.
If you wish to also add the belt/upper body side molding (B85) you can, its completely independent of the Conventional Two-Tone paint scheme.
Your truck thread on this question.
http://67-72chevytrucks.com/vboard/s...d.php?t=624582
Molding usage
http://67-72chevytrucks.com/vboard/s...d.php?t=572206