Bought breaks but....

Brakes. :p

I'd say no about the rotor, since they're typically pretty well coated, so they don't rust. Otherwise, it shouldn't cause any issues and would probably clean up easy enough.
 
Sounds like they didn't coat them before sending, or didn't fully coat them.

If it's just a lite surface rust, then don't sweat it. All brakes end up like that, as stated.
 
Sounds normal to me...

On another note, make sure you paint the hats @ the center of the rotor before you install them or else they will rust after a day or 2 & will look like azz....



Tape up most of the part that will be scrubbed by the pads, but paint a little into the area the pads will touch, that way once you brake for the 1st time, it will create a nice even circle & will look factory...
CIMG3168.webp

DSC_0002.webp



After braking...
DSC_0034-2.webp
 
Sounds like they didn't coat them before sending, or didn't fully coat them.

There is no Coating. The brembo rotors come bare steel. Introduce humidity and they will rust.

Even if they didn't rust in the box, they will rust on the car. Wire brush them and paint the hats before installing them, or you will have nice brown rotors shortly.