looks like a selflocking nut and there is a hole for a cotter pin or clip but I have not seen BRP use castle nuts... lots of locktite and selflocking or nylock nuts...
Don't know about right but you could add or have the dealer add a cotter cip...
2012 RS sm5 , 998cc V-Twin 106hp DIY brake and park brake Classic Black
Being a dedicated forum member, I just walk my bottom out to my cold garage to see if I had the same nut. See photo. It would be easy enough to put a Cotter pin in there if it makes you feel better/safer.
I am an ex BMW rider (aka anal retentive) so of course I had to go look at mine. I don't think it needs it but I will be adding a cotter pin. Sort of like safety wire at the track!