These scales are as mentioned solid, not hollow like the current cellidor ones for 91 mm. They are also profiled (sculpted) on their inside face in order to fit as best as possible.
Again, these are Victorinox scales, not custom.
Mounted not just snap-in as cellidor and nylon but with the use a bit of glue on the rivet ends (not a continous glue layer as for example on the rosewood scaled 91mm).