Never a whole system.
But I've bought the exact same part in July for less than what it was on BF/CM.
Do not count on getting new current model parts for less than what they are today.
BF/CM is merely a marketing term for the time between 1 Nov and 15 Jan.
This is when retailers try to suck people into the hype, and foist off last years stuff that did not sell, at 'big discount'. And of course, "Only 3 available at this price!!"
The best time to buy parts is when you have the money, and when you need it.