Sorry...One more Spange question

[Biro]

Maybe someone can help me out......

I read on the Iron Cross reference section of this forum, the following about the EK2 Spange

It was initially constructed from high quality silver-plated white metal with attractive highlights, but as the war dragged on silver coated or painted zinc was used.

And in Gordons book.....

The clasp was struck, initially from Tombak, and later from zinc.......

And then I saw this description on Detlevs site the other week...

Bar to the Iron Cross 2nd Class 1st Model, Zinc, reverse two prongs to attache on the large medal bar...

Can someone explain to a newbie, how a 1st model can be both '1st Model' and also 'Zinc'?? I'm not making any suggestions, I'm merely confused!?

Thanks in advance