460 or 460L? Visual clues.
 

Are there any physical characteristics that make it easy to tell the two apart?
Or is a 'long' look the only difference?

No visual clues other than the rear badge saying 460L instead of 460.

I've seen a few swb ones with "L" added on.
Most of the "L" have an Airshock adjust switch and height switch in the shift console.

But I have an "L" that doesn't have air ride..!

It takes a trained eye to be able to see the car from the side and tell if it's an LWB or an SWB so I think the only way was to rely on the "L" badge. There's no distinction amongst the head lights, grille, wheels, etc.

On another note...Why in the world would someone add the "L" badge to a SWB? Things like that make me laugh. Although my personal favorite is the folks who change the badge on a Chrysler 300 to the Bentley badge...

The same people that put "sport" badge on their front fenders. Maybe they think the "L" is for Luxury.

The rear doors are longer, but unless you're accustomed to seeing an L, it's not obvious, even though it's 4.something additional inches.

If you can look into the back seat, the legroom is amazing and you'll notice.

I'm not certain why, but the W126 Mercedes was much easier to see the difference, even though it's the same method of adding extra length. With those, however, SWB models were somewhat rare to see, so they stuck out. They looked 'wrong'.

jrmckinley and JWAS, yet more proof people, in general, are stupid.

I've always looked at the top of the rear passenger window, you can see that it is elongated compared to the SWB window.

I agree it takes a trained eye to tell seeing the 460 from the side. I've had my LWB for years and its easy for me to tell.

Rear door on the L is almost the same length as the front door. Easiest way to tell from a profile shot. I've seen an L missing the badge.