Fiducial marks on board vs panel
It depends on the size of the components, pitch sizes, density of the board, and P&amp;P device as well.

Here is a good fiducial usage example that are placed two corners of the  0.5mm pitch ICs. 



On the below panel, I only had three 1mm fiducials on the panel, and my manufacturer did the job correctly. 



Generally it wouldn't hurt to place fiducial on the board or corner of small pitch sized ICs if you have space. If you can't place them for some reasons, then consult with your assembly house.