There is hope.
I found mine (05 HSE) with the rear locker / HD package. Had to look but they are out there.
The easiest way to tell -- for example if you are at carmax or a LR dealer looking up and down an aisle -- is if it has a full size spare. Then make sure its actually got the rear locker (wires / plugs above rear diff). I did look at one 2005 truck that had a full size spare but NOT the hd locking rear differential. Prob the previous owner just put the full size spare on himself.
And likewise I bought a truck with a rear locker but no full size spare because someone must have swapped it. Looking in the pic for a spare tire is the easiest way to tell though and I'm sure my situation is rare.