Quoted from Mrbill:

if its cheap enough, throw the computer monitor in the trash and find a crt for it. if they did not mess up the mounting, it should be trivial to get a crt back in there. depending on where you are, a centipede is $500+ game. Replace the cp overlay. I would not replace side art. if it needs new side art, pass. if it has water damage, pass. MAybe ask the guy if he still has the original monitor. g07 is fixable and doing a tube swap is possible.
I think arcadeshop sells a big blue that is grey. I have only bought my big blues from bob roberts which are black. So if its not the light blue color, its probaby been replaced recently.
recapping the ARII and possibly repining the edge connector are things that should be done. You can also look up sense mod and decide what camp your in if its something you want to do.