Looks like more stores are seeing low stock of the 2015 Macbooks of various lines including the Air and the 12" Retina one. Good deals can be found on Best Buy while the 12" Macbook is no longer available. As far as last week, sales in the stores have stopped. So this does mean updates are coming. Best guess is April.
And the refresh will happen without an event like Apple traditionally have for the iPhone, iPads, and the Apple Watches. Mac sales have been strong and despite what many in the Apple community, specifically Mac users, fear, Apple will not be abandoning the "trucks" of the computing world as long as there are tens of billions in profit to be made.
Many considered the PC war to be long over and Microsoft's Windows dominance firmly established, but there are still areas around Microsoft's turf that Apple can nibble around - specifically, the segment of the market where PC costs more than $1000. And even as deals have pushed Macbook Airs down to around $800, it looks like Apple has relegated PC makers to a vast but largely unprofitable piece of the PC market.
More and more folks are abandoning PCs for mobile devices as their primary mobile weapons of choice - phones and tablets. Even here, Apple's iPads dominates those that cost more than $400.
We will continue to see Apple churn out high-end Macs for years if not decades to come. And the last refresh should be available in April. Keep in mind that Apple may not update all the Macbooks but it does appear that the Air and 12" versions should see the light of day while there are talks that Apple could hold off the Macbook Pro until June when it holds its annual World Wide Developer Conference.