The Used Bike Buyers Guide has more than just framebuilders in it, it also has a section on inspections of used bikes. Here is the excerpt for the Head tube. I believe this inspection will give the elongated headtube result that Jose shared. Lou Deeter, Orlando FL
Head tube: Is there a decal, badge, or engraving? Is it lugged or lugless? Does it have long or short point lugs? Inspect for cracks, gaps in the brazing, file marks, and rust. Note paint chips, particularly where a headset may have been previously mounted. If you have a headset, attempt to put the cups in by hand. You should not be able to do so. If you can, it may indicate an enlarged opening (contributed by Jim Cunningham).