Noooo, hopefully the little white frame liner guides will be in good condition, we mean the metal cable itself as the inner cable, and the black guides from the brake levers/shifters to the frame as the outer cables!
If you can get away without having to mess with the internal cable guides then do so, they will be a royal pain in the **** to get back in once pulled out lol!
And for old cable removal/new cable fitment, invest in a good pair of proper cable cutters, and cut your old cables cleanly and pull the nicely cut ends back through the frame guides, if the old cables are frayed or split, and you pull those bits back through the guides it will/can damage them and the outer cables inner sheath too, always chop and pull out clean so as to maximise the longevity of your cable guides and outers!
If you can get away without having to mess with the internal cable guides then do so, they will be a royal pain in the **** to get back in once pulled out lol!
And for old cable removal/new cable fitment, invest in a good pair of proper cable cutters, and cut your old cables cleanly and pull the nicely cut ends back through the frame guides, if the old cables are frayed or split, and you pull those bits back through the guides it will/can damage them and the outer cables inner sheath too, always chop and pull out clean so as to maximise the longevity of your cable guides and outers!