that 72 is not stamped into the the head tube but rather the lug. it is an angle stamping and should have been
sanded/ground/removed b4 painting. the Union hub is German made and very low end. the wholesale price when I
had my shop in the early 70s was about a dollar. the Weinmann ratcheting barrel adjuster came out right after
Suntour ratcheting shifters which were very popular so companys without any real new ideas were adding ratchets
to everything