I made a head badge, etched with an ungrammatical Latin tag, for my second comprehensive bike build/rebuild circa 1972 (complete strip, repaint, and rebuild of Alvit Varsity), and am quite clear that I didn't drill and tap holes for mounting screws (I was 16 or so and had never heard of such a process) and I am even more sure that double sided tape was not offered. So even Varsity headbadges must have been mounted with screws? Can anyone say?
Note: The rehabb'd Varsity was a work of teenage art (black gloss, hand pinstriped, half-stepped AW with Cyclo Benelux rd and single front ring, whitewall tires, shiny silver aluminum fenders) but when I next fingered one some 40+ years later I was shocked at what a dog it was. A very well made and sturdy dog, but a true dog.