1999 Chevy Camaro Putting caliper back on after replacing b

I purchased replacement pads and a new roter, but am not able to get the caliper back on the caliper bracket. The plungers are fully in, and the caliper fits nicely over the roter. But I cannot get the caliper to go over the bracket to bolt it on. On the bracket, are the caliper bolt holes adjustable? I'm thinking they are, but are rusted firmly in place.