Some are patched AR codes while others are hacked routines for the binary (which operate on the same parts of the memory as the AR codes). Ultimately they all do the same thing and hardpatch action replay codes as you say.
Note there are the trainers which add all the cheats in the list and unpatches which remove them one by one.
Truth be told while they work they were made using some older methods and cracker now recommends you use DSATM instead.
Lol yeah. I bought an n5 not too long ago(three days after Christmas of 08) and I really love it. A lot cheaper than buying DS games at stores, and I hate playing gba games and nds games using emulator on the computer. In other words, I'm try to find every part of information that I can figure out about the n5 and ds hacking.