If you are concerned about copyright take legal advice. On the three occasions I've been to court on copyright issues over the past 25 years, all have been won on properly identifying copyright ownership. In the last case the court considered the lack of proper copyright identification to be mitigating circumstances and did not consider a brand or logo suitable. After all the copyright symbol is built into most keyboards so its application is not an imposition. Having a digital copy is no longer a guarantee of ownership either. It's all in the documentation (subsequent proof).