On the cover I'd run a fine flat file across the surface to take off any burr - but that "dent" is not anywhere that will cause pressure loss.

Likewise with the rotor and stator, I'd clean it up and make sure they don't bind but otherwise I'd run those parts with no fears.

Clean up the ding in the pump body also. The pump body is just a housing for the stator to rotate in, it could be full of dings but as long as the stator has the proper clearance and rotates freely it won't affect performance of the pump.