Just trying to make sure if I have figured this out correctly. Stamp on bottom of seat tube says made by Gazelle. It has the italicized block downtube lettering. The only serial number is on the BB. 2906565. Most sites say if it is 73 it will have 7 digits beginning with 0. This one doesn't. Altenburger calipers etc. Simplex derailer. Atom mm pins, hubs marked Normandy made in France. Sturmy Archer chain/spoke gaurd on rear hub. Brooks saddle appears to be original.