John,
The sink covers were custom made at the factory. You may check with BCS (Beaver Coach Sales) to see if they have a source for reproduction covers or Northwest RV Supply in Eugene Oregon my even have some old stock, but I doubt it. If those two sources do not work, you next option is to start calling salvage yards. However, if you take the exact dimensions to a solid surface counter fabricator he can probably make you one without the Beaver logo but the color will probably not be an exact match.
Gerald