They're called Pan Head screws and are 6mm x 1.0 thread pitch. Although I'm sure you can source it somewhere other than Honda, I've had a hard time finding an exact replacement but if you're not picky I'm sure a nice Allen head bolt and a fender washer would work.
Sounds like you are asking about the plastic trim clips Honda calls 'clip, drive chain case'. The 6th gen requires two of these. They are part number 90684-MBG-003 shown here as #18: