Wait, I just saw this.
"I don't have any way to check IVs. I've been holding the Pokewalker and DS most of the time. A couple times I've had the DS sitting on a table."
Find an IV calculator(Serebii's IV calculator), request an "IV battle". Then, go to the wi-fi room and do a lv.100 battle with that pokemon in your team. Enter 100 in the pokemon's level, then enter the stats. After that, select the calculate button, and you will see the IVs.