The final look of your veneers is really in the eye of the beholder. What I mean is that in the end you want to wind up with porcelain veneers that you really love!
Your veneers ought to line up with two key places: the alignment of your eyes, and the outline of your lower lip.
It's hard to tell in your photo how they align to either of these.
To answer your question, YES, some slight modification or filing can be done after your veneers are cemented, but I do it very cautiously, as once it is off, it cannot be added back.
Also remember, your face is not absolutely symmetrical, neither are your lips. While your veneers ought to blend in and look natural, they may not look identical when you compare the left and right sides.
Take a few photos from different angles, ask a friend who's opinion you value, and then make a very short list. Ask to speak with your cosmetic dentist for a follow up, and get his input too.