You're not required to use the ® and ™ marks to denote trademarks. Look at the web sites for Apple, Twitter, Facebook, etc. No ®s to be found. IANAL but as far

You're not required to use the ® and ™ marks to denote trademarks. Look at the web sites for Apple, Twitter, Facebook, etc. No ®s to be found. IANAL but as far as I understand it, the purpose of a trademark symbol is to save you from having to send C&Ds to unwitting infringers. Your trademark doesn't lose its status just because you left of the registration symbol.