I ordered my Sieber track frame and fork in 1948 from the factory through Joe Dignan's bike shop on North High Street in Columbus, Ohio. I don't remember drilling for brakes even being an option. I do remember that since both the frame and biplane fork were chromed, any combination of paint and chrome could be ordered. Chrome lugs with painted tubes, chrome ends, etc. I went for a full chrome fork and painted (translucent red lacquer) frame with chrome drop outs. The idea of drilling for brakes was heretical and far worse than sacrilege. I used inch=pitch block chain because that's what everybody did. My first rims were wood-filled alloy tubulars, after that all were alloy. The wood-filled rims were ruined at the National Championships in 1949 when another racer put a pedal into my front spokes at speed. Tires were "open-sided" silks. I only used wood rims for training. They were mounted with "US Mules." Black rubber US Royal tubulars that looked kind of like garden hose. Only less compliant. I raced the Sieber from 1948 through 1951, and sold it in 1952 complete for about a week's wages. And yes of course I wish I had it back.
Mark Fulton Redwood City USA
PS: My prejudice against drilling for brakes continues today. You can see my Steelman and Waterford track bikes on Fixed Gear Gallery. Both have road race forks. I also have a couple of Bianchi Pista Concepts and a 3Rencho track bike that I've built up the same way.