Here is a good article on this album cover. It is a space ship shaped like a guitar. What ever the four things that are in the bridge position the artist only knows. But the guitarist said he wanted a guitar and the artist came up with that..... For Boston, More Than an Album Cover
I converted a 6 string Modulus to a 5 and left all 6 tuners in place. I just replaced the bridge and nut, so that's probably what happened here.