Yes that is basically what we are saying. Turn your SKS upside down on your bench, flip the safety to the on(horizontal) position, then while pushing forward on the FCG(trigger group) latch release pull upward on the FCG. It might take a good bit of pressure but don't worry about that, it is normal. You do not have to remove the top end of the rifle to get the FCG out but if you already have it apart that is fine too. After the FCG is out and with the bolt assembly either back and locked or out you can then remove the mag.
FYI, there is a video on youtube for the disassembly of the SKS that you might like to watch.