The 1274 number apparently just refers to the number of days Armstrong was 'retired' back when. It doesn't appear on any Livestrong models I found photos for, just on the Madone 6.9 Pro the company built for him.

"The number 1274 represents the number of days Armstrong was retired before making his comeback at the Cancer Council Classic in Adelaide, whilst 27.5 represents the millions of people who have died from the disease in the time since the seven-time Tour de France champion stepped off the podium in Paris after sealing his last Tour crown."

Lance Armstrong's Trek Madone 6.9 Livestrong - BikeRadar