Are the mounting holes in the old caliper the same diameter as the new one? Just reuse the old bolts or buy new ones that are right as long as they fit through the caliper.
When I did my water pump it came with fan mount studs that were metric, they didn't even fit in the pump they came with. I went to parts dealer and he told me there shouldn't even be studs packaged with it. Reused the old studs and boom, all set. Perhaps you got "lucky" like me and got the wrong bolts.