The Dually spacer for the rear end isn't to make it a dually in your case. It would space the newer wheels you are wanting to use out so they fit right. They have such a shallow backspacing that they would be too far inboard to look right without either a wider axle or the spacers.
I'm heading out for Thanksgiving, but I'll take some pictures when I get back and post them. After all, a picture is worth a thousand words!
Craig
