iro frames are chased and faced from the factory. you shouldn't need to do any of that to a new frame.

really, any new frame should be ready to assemble with a gxp or any bb.

if you paint it or powdercoat it, then you'll need to do one or both depending on what was masked and how.
usually that isn't necessary... but you need to take great care when installing a bb on any frame as crossing the threads can quickly destroy the frame. just make sure it's not difficult to install the cups/shells and if it is difficult that it's not getting significantly more difficult the farther in the shell goes. if you're not sure about what you're doing, get it installed at a shop unless it's a frame you can afford to mess up.