mine had one more leaf spring on the passenger side...when I removed it I think that caused it to sit a bit lower..( i wanted 6 remaining on each side) springs wear at different rates and over time one side may drop lower..I replaced my shocks,(NAPA has them) my shackles are really bad... I noticed when my axle was off they wiggled...and one of the front ones sat straight up and down and the passenger side one sat at a 45 degree angle forward, that would cause some drop in ride height..
This is now just another thing on the list of parts to upgrade and replace..
but my WHEELS all sit over to the driver's side... front and rear..
I spoke with some some friends who know old cars, they said the bodies were never put on straight from the factory...