Does your dealer deal in cars and motorcycles?
No. Just BMW and KTM motorcycles. That's a screenshot of BMW provided software that my dealer uses.
P.S. You do know that BMW owns Mini, right: "With its four brands BMW, MINI, Rolls-Royce and BMW Motorrad, the BMW Group is the world's leading premium manufacturer of automobiles and motorcycles and also provides premium financial and mobility services."
Your second question seems to be, can I buy it at one BMW dealer, not my own BMW dealer for instance, and still use it at any dealer, including my own BMW dealer?
My dealer told me the fine print was in "your manual you received when the bike was new". I downloaded that manual from...
BMW Motorrad stands for passion, dynamism, design, technology, innovation and, above all, quality. Based on this conviction, your authorised BMW motorcycle dealer is extending the statutory warranty for your new bike by one more year starting with all 2019 models. Enjoy peace of mind for 36...
www.bmwmotorcycles.com
...it says...
To obtain warranty service coverage, the vehicle must be brought, upon
discovery of a defect in material or workmanship, to the workshop of any
authorized BMW Motorrad Dealer in the United States (including Puerto Rico)
during normal business hours.
The authorized BMW Motorrad Dealer will, without charge for parts and labor
(including diagnosis), either repair or replace the defective part(s) using new or
authorized remanufactured parts.
Seems pretty clear to me. It's language like this that makes manufacturer warranties so much better than third party's "extended service contracts".