I got the same notice along with my HOG magazine the other day. My red tail works just fine. On either side of the rear fender there is a red reflector about the same size as the yellow ones on each side of the forks.Just got a letter from HD in the mail today - Safety Recall.
NHTSA Recall No. 15V-217: a red reflex reflector on the rear of the motorcycle (p/n 59988-72A) may have been omitted from your m/c.
Sure enough mine doesn't have it. May not be a huge thing - but may save someone's life.