The below Part numbers are from the 800 models, 155" and non-3", so you can dig those up if you need to see if there are any differences in the 850 and 3" rails.
2016 Assault (Non-Axys/Pro Ride - Didn't come as the Axys in 2016) All rails the SAME AS THE PRO RAILS
2017 to 2019 (NO Assault in 2020) Assault Natural Rail Part #1543527-309 LH / Black Rail Part#1543527-067 LH / Red Rail Part#1543527-293 / White Rail Part#1543527-599 LH / Orange is also available and LMSQ???
2016 to 2020 PRO (Axys) Natural Rail Part #1543448-309LH / Black Rail Part#1543448-067 LH / Red Rail Part#1543448-293 LH / White Rail Part#1543448-599 LH
2016 to 2020 SKS Natural Rail Part#SAME AS PRO LH / Black Rail Part#SAME AS PRO LH / Red Rail Part#SAME AS PRO LH / White Rail Part#SAME AS PRO LH
2020 Khaos Natural Rail Part#1544262-309LH / Black Rail Part#1544262-067 LH / Red Rail Part#1544262-293 LH / White Rail Part#1544262-599 LH
Best Part is how much more it is for a painted rail than Natural by hundreds of dollars. Most expensive paint job ever! I had a front clip of a car painted for less than the difference of 2 Natural vs. 2 Red or Black Rails. The difference is around $170.00 per rail!!!!!! I would sell those "Black" Assault rails and PRO Rails, go out and buy Ice Age Bomber Rails...... lol.