This can easily be confirmed using realoem.com or bmwfans.info and looking up the rear air springs/struts. The part database should list both springs...probably with the option code listed in the supplemental column for the sport pkg option.
Using the correct 11 digit part number for how your X5 is optioned..will also help you select the correct item on Arnott' website.
EDIT: just went to Arnott' website & entered my model, year, & SLS option. I was offered 4 springs...sport or comfort (left & right rear). Then when I clicked on a spring for more detail...it gives the BMW 11 digit part number. Kind of hard to make a mistake in my opinion regardless of which method you use. Comfort springs for regular suspension or sport springs for sport pkg.
https://www.arnottindustries.com/sea...el=64&year=162