DR Edi - about the "Colored Entrance" is it a sign or painted on the wall? I am totally into history too and think it would be interesting to leave it, but if it's a sign it could be removed and perhaps put in a display case with other items from the old days to allow people to see the historical perspective.
Or, you could leave it where it is and put up some sort of plaque or description next to it, explaining the historical significance for those too young to remember