I've seen them for the GS and IS but nothing for the RCF.
I mainly cruise around in Sport mode haven't really used Sport + other than to really scare my passengers lol.
If you have just one Go Pro, I found mounting it to the left of the rear view mirror works the best for me.
Congratulations and welcome to the forum. I have no LDA button on mine either. I know there is supposed to be a button on the right side of the steering wheel. If it makes any difference I have the performance package too.