The ESP Guitar Company

Hey guys, I a purchased this 2008 ESP M-II NTB from Guitar Center the other day and wanted to see what some of your thoughts are on the condition of this guitar. I bought it with a two year warranty and was wondering whether or not it's worth holding onto or bringing it back in for a return. This is my first ESP guitar and I'm not too familiar with it so I'm hoping you all can maybe shed some light.

The first thing I noticed is the selector switch is not functioning properly. You can toggle between the 3 pickup settings, however, on the bridge pickup it appears that it does not make proper contact and the sound is still the same as the middle position. If I press on it a little bit while engaged in the bridge position I can hear it make contact and the sound changes to the bridge pickup, but as soon as I let go you can hear it's back to the middle position. I'm sure replacing the switch alone will not be hard, but I opened up the back and am unsure whether or not there have been any changes made to the wiring. Here are a few pics of the back of the guitar:

I see a few extra holes pictured here, which I assume should be for the ground, however I do not see a ground wire running from the bridge to the pot.

I also noticed this hole here at the back of the bridge behind the the plate that holds the springs. What is this hole for? Was this a modification also done by the previous owner?

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Can someone please explain to me what's going on here and what modifications have been made?

I also noticed the previous owner had replaced the Gotoh tuners with Grover tuners. The Grover tuners did not match the position of the screw hole on the back of the headstock from the Gotoh tuners and they appear to be screwed a few millimeters below the original screw hole. The original screw holes appear to have been filled. Should I be concerned about this? 

Appreciate you all taking the time! I hope I can come to a better understanding on all this, cheers.