I have to doubt that the KOR shot is a glimpse of the future simply because Kylo loses both his mask and his lightsaber by the end of TFA. I’m betting he’ll have a distinctly different mask (if he has one at all) and a more traditional saber the next time we see him.
Yeah, that’ll probably be the case, but as Haseo did point out, Rey does have a vision of her fight with Kylo from the end of the film where he wears his mask. He also “sees” her during her vision of the KoR, so obviously her visions aren’t completely objective. So many of these moment might be from the future, despite her seeing the people involved as they currently are. Or Kylo might have partaken in the massacre with his old mask and saber had she not defeated him on Starkiller Base. So it’s not impossible that we’ll see and alternate version of her vision.
(PS, yes I know I’m stretching here, I’m just saying it’s possible.)