And if you want to find out if the other outlets are ground go buy a simple plug in tester for about $7.00 at Lowes or HD.
There's going to be a sticker that comes in the GFI box that will say something like GFI protected but no ground. It needs to go on the outlet cover.
If you pull out the outlet from the wall first make sure the breakers off, If there's two sets of wires attached to the back of the outlet your going to have to find out which wires are supplying the power to the outlet (line) and which one are what's feeding the outlets down stream, (load)
Your going to have to deconnect all the wires, make sure none of them are touching, turn the power back on and use a volt ohm meter on any white and black wire to see where the incoming power is coming from.
There's going to be a sticker over the bottom leads on the GFI. The incoming power goes to the top of the outlet marked line and the down line wires go to the load side.
White wires go on the silver screw, ground goes to the green and black goes to the gold screw.