Screw in the BB in and look at it. If the threads play nice and everything is sitting square, why chase and face? If you have a good touch with a wide bastard file (draw file) and blue machinist die, you can clean up the face if needed. There's a chance that the frame is good as is, and if you pay someone to 'fix' it they will make it worse. This only applies if Surly has threaded the BB and it's all pretty square out of the box.