Yes, that is correct. Your channel will still "live" and continue functioning after Jan 1, 2019. The components will not be removed from the firmware on that date.
To Destruk's point, though, those components have been deprecated for close to two years now, and Roku has not been investing in their continued functionality during those two years. To that end, it's to be expected that the channel may become unusable at some point in the future as successive firmware updates make the channel less and less optimized.