I worked for a long-defunct optical contractor in the late 1960's. Customers ranged from NASA (Apollo Command Module Windows, and an entire Solar Optical Tracking and Observation telescope network, arranged worldwide in an equatorial line, over a dozen altogether), National Bureau of Standards, Sandia labs, etc.
We performed assembly to extreme standards, but did not produce any of the optical lenses, mirrors, or plates it employed. They come from sources ranging from Zeiss to Edmund Scientific. In some cases, one contractor produced the glass blanks, another did the grinding and polishing, and yet another did the coatings. We did the mountings.
My responsibility was to engage and follow all the subcontracting. Among many items, Fabry-Perot Interferometer Plates and Spacecraft Windows, commercial camera lenses and $200,000 NASA telescopes (in 1968), my mandate was always the same. It gets done right or it get done over, and done over costs people their jobs, myself included. In some cases, that potential included intangible treasures like the lives of American Astronauts.
As stated above, originators make products to all standards, and the important component is not something you hold in your hand, it's something you hold in your heart.
While it's not often possible to make relevant determinations with the naked eye, one eventually develops a 'critical eye' for quality, maybe from the sheen off a coating, or the shape of the distortion in a reflection against a white wall. I have lived through the Made In Japan prejudice, and see it now in the Made in China antipathy. The name of the country mean little now, less than before, will be less yet to come. The Japanese have earned a good rep and the Chinese are coming along rather well too. There was a time when things made in Germany held an almost mystical reverence; this may still be so, it may not.
The important name is the one on the box, and the esteem in which they hold that name, their own name.
Greg