There's no reason why you shouldn't be able to. If you try editing it and it doesn't work, try setting it to read-only. Or you could just use the trainer

Word of advice for anyone wanting to edit .ini files: Download Notepad++. It's a free program and makes it so you can edit all sorts of various game text files, as well as uses much more legible parsing for lines. More convenient, and won't cause problems if the file was saved a certain way.

1: The Premier Club unlocks (Golden Key, Gearbox weapons, relic that increases chance to find rare loot)

2: Monster arena dlc thing from Gamestop.

3: Special Edition character heads and skins.

4: Some weird grenade mod that turns your nades into fireworks. Cool looking and decent damage, but hard to use since they fly straight up into the sky.