Any Gen 1 rear rim will work on a non-ABS Gen 1. If you use an ABS rim on a non ABS Gen 1, you only need to swap out the grease seal on the brake side of the rim. I'm running an ABS rim on my non-ABS 05 right now. I bought the extra rim to try darksiding and never went back. I've been running it for over 3 years with no issues.
BTW, I have a non-ABS rear rim off my 05 for sale if you want to come to AZ and pick it up. It's too expensive to ship.