So, when you drill plastic, some of it melts, and sticks to the larger piece.  It should snap off very easily.  Yes, a vendor should have cleaned that up before you got it.... but... c'mon.  Push a nail through that hole and it'll be fine.
Also, how exactly are you ill equipped for trimming control panel artwork?  Mount the artwork and run a knife around the edges of your control panel.  And, yes, that's how all control panel artwork is done.