If you still have bump stops on the frame and they're very very close to the axle you have stock springs. Or what he said /forums/images/graemlins/wink.gif Negative arch means stock springs... What about the back? Any lift blocks?
Sounds like a stock HD package to me. 5 and 6 leaf packs were avalable in the rear and 2 or 3 leafs in the front. 31's were also an option. Yes you can fit up to 33's on the stock suspension with very little rubbing. (trying to keep the posts down in the garage /forums/images/graemlins/wink.gif)