So I go to finally change out the stock pads and rotors and instead of bolts there is some type of allen key thingy to remove the caliper.

is this a special tool or will a standard allen key set suffice to do the job?

Any help would be appreciated

(the car only has 57K miles on it which is why a brake job was never done)

 

You'll need a 3/8 allen socket.

 

Which has been a GM standard for a long time.