Yes, it appears to be true. The Vintage Tulip postage stamp is sold out after three short months of disclosure. It seems the USPS underestimated it’s appeal. It will be re-released, I am told, as a 71 cent stamp whenever the postage rate changes. (We shall see.) In the meantime, you may find stragglers at your local post office and on eBay. And of course, there is alway the Vintage Rose “Forever Stamp” still in circulation. Small consolation for all those young lovers about to be wed. (The 70 cent Tulip stamp is the current rate for mail weighing up to two ounces.)
More info can be found here: http://www.linns.com/news/us-stamps/1842/2015-70