Yes, I think I’ve seen those kits on ebay some time ago.
They came after a search for wooden frets for 8000’s – same kind of mod to me :BL18 look alike.
If I recall well they were available for BL6000 too.
As Millemissen, I wonder how they can actually “upgrade” the 8000’s sound, but as lot of people as them for the style only part of me can understand.
I aslo find 8000’s with wooden grills but without ALT looks weird and unbalanced: that may be an answer for this, without altering the sound of 8000 by ot moving the actual tweeter.