There are lots of other differences besides. I don't own a SWB and I'm sure I don't know the half of it but here's what I can think of off the top of my head.
Single battery on driver's side (vs. two battery boxes).
Front bumper weights
Different front bumper mounts on tub?
Early SWB cars didn't have adjustable strut towers
I think the shape of the sheet metal 'shelf' behind the fuel tank is quite different (the fuse panel is up there too).
Vents inside cabin at front inner longitudinals
Rear shelf is ribbed
One-piece knee guard (in lieu of two plus ash tray)
Copper window frames
Four-hole grills (196?)
Engine lid/grill
Rear vented windows
Seat belts?
Tail lights and buckets
I'm thinking I've not scratched the surface here but I've run out of ideas.
Hey! You have one! Lucky guy
Tim K