sorry over the double post,I forgot to sign off.
The builder "Gios" most likely drilled a very small hole in each tube and after the total braze, he went back and brazed a drop of silver or brass onto the holes and polished smooth.
A good portion of us do that, the theory is if air can't get in neither can water and if either of them can't get in than there will be no rust. so, don't drill any holes, if you can get some Frame Saver spray it into the open tubes (seat tube, chain stays, down tube, head tube ) and ride like the wind. God Bless, Anthony Mezzatesta Mezzatesta Custom Cycles 909 Berkley Manor Dr. Cranberry Twp, Pa 16066 724 498 4191 http://www.mezzatestacustomcycles.com