They introduced the metal decal in 1946/7, immediately following the third type of water transfer paper decals they were using up to and including WWII. If you search on "logo" on the SK thread there is much more detail provided in a few posts. EDIT: Relevant post in SK thread is linked here.
If it will help, I bought these new in 1954.
This is from the set I got from my wife's grandpa, could have been as early as mid-50's or as late as mid-80's based on when he was working. As far as the label itself, I have no idea.