No locking cap.
In the instructions it says to use a thin plastic putty knife. I think this is to long and really to fat to get underneath.
I used a skinny flat screw driver - shoved it in and pryed back a little. The existing filler cup pops out in each section. Yes you may scuff a little bit of paint but this is little this way and not where it can be seen (since it will be covered after re-install.
The drilling isn't that difficult because a very nice template is provided. I just started with a small size and kept working up in sizes to make the drilling easier.
I think the best advice I can give is - since the new cap has some room outside the chrome you could potentially mess up [a little] and still wouldn't see because the black rubber would hide it. The template works well and I think anyone that takes there time could do a better job then someone at a dearlership.
Not better because of skills but because they are patient and their boss isn't hounding them to hurry. This doesn't take any mechanical skill or no-how to do.
Maybe just the no-how of which way the bit needs to turn.
