Originally the chain case came with a "pie plate" which held a sliding cover plate. Covered up the black sprocket, my '52 parts bike is like that. You have a great start! Add fenders and brooks saddle. Add black grips (all the gray originals have rotted and gray is a hard color to find new). Nice start, what state are you in? I just rebuilt a '55 using some parts from '51 and '52 ladies parts bikes and a '55 parts bike, if you need advice. And expert advice and dating can be gotten in the fb raleigh roadster group based out of UK but is worldwide. P.s. the seat lug stamp is by manufacturer and is the main dating clue and sometimes also under the bottom bracket.