First US dealers wanted true premium prices for glass grips. At these (early) times here nobody took any notice of the different kind of grips. One of my first armies I have bought (and still have it) was a nice patinated EICKHORN with pure ivory grip for the price of a "normal" dagger.
In the meantime simply the dealers here do what have was done over the sea long before, gain premium prices for any "extras" like glass grips (mainly without knowing and taking care what they really are....), "rare" manufacturers and so on.
As said, I for myselve never have seen a true amber gripped army, only those imitation ones. There would be the destructive hot needle test (I do NOT recommend because of irreversible damage) for those who cannot judge it by view.
Simply show a good, detailed photograph and an overall one from front and side here, tell the manufacturer of the dagger (if there is any) and I will try a look.
I think I know the "Bernstein" grip here and would not worry about it.
Regards,

wotan, gd.c-b#105

"Never look for sqare eggs" as a late owner of an original FHH-dagger used to say.