Non-Serial Xmetals

[Mike.vanderkoon]

It’s a perfectly logical assumption and in line with Occam’s Razor; it also requires the least effort.

Basically, there’s no such thing as a matching fourth gen box because there is nothing on the glasses for the box to match against.

I’m not saying the match 4th gen but instead owners that know their box is original—eg original owners—show there number on the label. We then compare that the number to matching 3rd gen sets.

 

[Carrera1963]

By the way @toosteeley , the A-prefix just happened to coincide on the boxes you show, it’s not universal as the above photo shows. The third box from the left is from a fourth gen pair - the serial is clearly higher than the earlier pairs.