The lenses and the inner housings are the same however the mounting box on the outside are not interchangeable.
Hence, if your lenses are cracked and need replacing, just go to a scrapyard and you will find many AE82 headlights easily and cheap.
If you've front ended your AE86 and your lights are busted ... good luck finding another Sprinter in a scrapyard! Most that I come across have frontal damage - no doubt testament to the ability of many AE86 drivers out there ...