Replacement time, and brake bolt rubbers question

[SirDigby]

yea. the rubber is stretched into a groove. be gentle. grease them pins good!
as to the rotors; if you have a second car, you can take them you get measured/machined at a NAPA or some other parts stores as well as machine shops. the parts stores will have the measurements on their computers, the machine shop will be able to measure with the specs you pull of the internet. (idk what they are)
you can return the rotors to where you bought them if you don't use them. if you keep them, store them upright, like books, to keep them from warping. (most everyone stores them improperly, even parts stores. it's a good idea to get NEW rotors machined in some cases)