Those foundations are to be named after 12 Apostles of the Lamb.
Does that mean Judas gets his name up there even after betraying the Light?
Or is Matthias the 12th because of the casting of lots?
Or is Paul because he was a chosen vessel?
Or is there a future 12?
If there is a future 12, they will probably not be looked at as more valuable than other stones, but the Light that shines through might be unmistakably brighter than any living stones that walked the earth the last 2,000 years.