I've seen a bunch of these questions and I just want to be absolutely positive that I'm doing the correct thing here. 

I have about 2-4 wall outlets per bedroom - all of them on 15amp breaker(s). I would like to replace them with 3 prong outlets. 

Each outlet (aside from the last on the line) has 6 wires (black, white, bare copper - in/out). The bare copper ones are pigtailed together and attached with a screw to receptacle. 

To replace, do I just need to:
1. 15 amp 3 prong outlet get a 3 prong outlet
2. Connect the black to brass, white to silver, and the pigtailed to ground in new outlet? 

[Photo of outlet with pigtailed grounds][1]

Anything different from above if I want to put in a GFCI? (Converting a br to home office with computer) - is the gfci necessary?


  [1]: https://i.sstatic.net/5vLuv.jpg