They went from a paper type transfer decal to a metal badge after WWII, in 1946 or 1947. If that's what you're asking. Check with d42jeep (Don) or the other SK aficionados on the SK thread for a more detailed answer, because there were a few variations of the metal badge. There is an A-Z Index of threads in the Sticky at the top of the forum. Click on the SK link.