If the original photo is blown up, There is a strange line running down the bolt. Looks like the robot left the bolt in the sand blaster or bead blaster, And beat it up instead of just blasting it to an even finish. That strange silvery spot on the bolt shroud looks like the coating came off to the bear metal, Or something was on the metal and the bluing or coating did not take.
It looks like it is not bluing, Because it covered the silver solder where the bolt handle attaches to the body. The solder line is visible on most blued bolts of Remington 700's.