Just did a quick measurement on mine. Rear is 12 3/4" from top of axle to bottom of frame rail, front is 9" from axle to frame. It has a 4" HFS lift that was put on about a year and a half ago.
I would imagine that any stock springs would have sagged a bit after this long, so getting a factory measurement would be difficult. IIRC there was a drawing floating around somewhere that shows factory measurements, but I'm not sure that included frame to axle.