Yep. That covers it, thanks. Saved me some explaining.
Edit: one thing it didn't cover really was that fresh cast Zamak is immediately polished and plated, before it has a chance to oxidize. It is pretty easy to initially plate.
Zamak is a pretty decent razor material, all things considered, especially if the threads are made from some other substance, like brass. A Zamak razor should be expected to last slightly longer than it's plating.