Your name of gliding metal is the old name for this kind of tombac. Even the what you look ( Wikipedia ) will give you same name like the alloys metallurgical books "enameled tombac" which are use today.
Your old name and the modern name are synonyms. Personally I use the last names but accept the old also because is hard to change people to the new nomenclature.
I give you here the specs of this alloy (you can check if I am wright):
ASTM B36, a cold roll alloy, yield 50Ksi, tensile strength 56Ksi, elongation on 2 inch 5%, hardness (Brinell scale)114
Hope at your satisfaction
PS the wright way to say on collecting will be just: tombac, brass and bronze.