I would like to add, Im pretty sure that Leupold who like many others outsource their glass, still has QC requirments reguardless of what country is selling the glass needed to them, that tue glass has to meet.
I work for a contract manufacturer. I can assure you that what you said about Leupold is true of just about any manufacturing business.
We just don't call someone and say I want to buy X without flowing down a detailed set of not just specifications but also fully detailed engineering drawings. And then we check when it comes in.