I have successfully transferred my dented 2011 MacBook Pro housing lid to a new one without any major issues. You will definitely need a heat gun for the job and a heavy duty suction cup. The suction cup will slide when the glass is heated up due to the plastic on the suction cup being warmed by the glass. The alternative is to buy an entire display assembly however note that there have been slight design changes in the 2011 Macbook. One thing that I missed are two plastic cap covers at the end of the hinges (near the slide clutch cover) when transferring to the new housing. That meant I had to disconnect everything and put these back.
yes - as with disassembly of any electronic component you have to remove any power source. You don't want to accidentally turn the Mac on
Note that the 2011 version differs from previous models at the connectors on the antenna end opposite to the display cable. Do not attempt to buy a complete display from prior models.