They're not L-body (Omni/Charger/Rampage/Horizon) items; those cars used the same 3587 436 and 3587 440 (amber and red respectively) sidemarkers as the '72-'76 A-bodies…no screw holes. They're not Dodge truck or van units.
The "82" does not necessarily refer to the year of the vehicle the lamp was designed for. It's part of the lamp function identification code SAE AP2 82 means this lamp produces a retroreflector function ("A") and a sidemarker light function ("P2") in compliance with the versions of the relevant SAE technical standards for those functions that were current as of 1982. The next part of the marking (W28 CC) should give more of a hint as to what these are for. The CC is for Chrysler Corporation. The W28 should be a body type designator. There's no "W" in 1982 or '83, but there is a "28", which means FWD pickup truck: Rampage/Scamp. However, those are "Z"-code cars, not "W"-code. Nevertheless, the rear sidemarkers for those mini pickups are not the "everything else used it" 3587 440, they are 4174 383. I do believe that's what you've got there. Probably external screws were used because of lack of access to the inner surface of the outer panel to tighten the quik-nuts onto the plastic anchor posts of the 3587 440. As for the "W" vs. "Z", my guess would be that Chrysler originally thought to code these vehicles "W", then changed to "Z" for whatever reason. It would not be the first time such a re-code took place.