Maybe a special Canadian importer brought some bikes in fitted with Dell Ortos, but I am also totally unfamiliar with any R65 models coming to the US with anything other than Bings attached.
I 've a couple books on the history of various airhead models and there is no mention of this in any of them, and it includes quite a bit of details of mid-year production changes, etc. Even the limited production run MotorSport edition RS bikes were fitted with Bings, and the 1980s emissions requirements would have made a factory variant with different carbs very unlikely. Still BMW has done bizarre things before..