It was sold as Giganteum Metallicum, but it does not resemble what Giganteum Metallicum pictures are out there on the internet.
Does not seem to react acutely to 3-3-3 fertilizer like I use. not sure if this info matters, but some cultivars react very fast to that NPK value.
Problem is the seller Germany) does not even have any Sempervivum for sale with pictures like this one, to try to see what else it could be from his inventory.
Pot size is the typical 9cm (3.5inch) one.
It's been out in the light for 2 months (around 4 hours full sun per day), so the coloring is well set for some time now.

It can really be difficult some times to compare photos of semps because of the different climates, fertilizer/no fertilizer, soil, etc.
But I can see that yours might be correct when comparing to some other photos of 'Metallicum Giganteum'. Try not to fertilize and see if the color changes and watermarks show up.

This photo was taken in August

Other photos i've seen have broader leaves than mine, in reality it is quite clear the leaves are narrower than many other cultivars.
I have 5 specimens and all are the same, this coloring as seen in the original post, I have that one using fertilizer (and max 4 hours of full sun) and others unfertilized and in 6 hours of full sun (another location entirely) and they are the same actually, leaves are also narrow, same coloring, all new leaves in the middle are growing red on all specimens.
As I was saying I got them for 2 months now and has been pretty hot and sunny here this year for sure, I was expecting the red to go, but it did not.

Just keep them tagged and see how they do in the next year.

Paleo unfortunately there are so many different cultivars it is a challenge to find a name for one after its lost it's label. I agree with you that yours doesn't look too much like Lynn's photo. And agree it is a good idea to see it in several different seasons to see those changes.

Then I guess I have to see what happens when fall comes.