Current B777,both -200 and -300 series do not have protection to avoid a tailstrike.Over-rotate and bang! The -300ER is from what i hear,going to have a system fitted to avoid this.Perhaps someone who is technically up to speed(unlike me) might be able to elaborate.Also,to answer your question,the -300 has an indication via EICAS to alert crew in event of tailstrike.(There is a tailstike leg,located rear underside of fuselage,which when compressed sends message to F/Deck. Electronic checklist requires both outflow valves switched to manual and then to open them both( depressurize cabin).Plan to land at nearest suitable airfield.
Hope this answers most of the questions
Safe flying all !