Your bearing shells are removable. The cam bearings will have to be taken out and replaced along with the expansion plugs (frost plug). Some shops still have a hot tank with a caustic liquid that is heated to clean your block and some use a furnace to burn the stuff off.
If you decide you want to re-use your main bearings make sure to keep them in order so they can go back into their same spot and also make sure to keep track of any shims under the main caps.
