Source, Wikipedia:

"Silver steel is common tool steel that is supplied as a centerless ground round bar (with tolerances similar to that of drill rod).
Amongst other applications, it has been widely used to make such things as punches, engravers, screwdrivers. Sheffield silver steel is used in France as a blade steel for straight razors. In Finland, German silver steel was and still is widely used for Puukko knives.

The composition is defined by UK specification BS-1407, and is as follows: carbon 0.95–1.25, manganese 0.25–0.45, chromium 0.35–0.45, silicon 0.40 max.[1] In the annealed state it has a hardness of 27 HRC. It can be hardened to 64 HRC.[2]

The European/Werkstoff equivalent grades are 1.2210 / 115CrV3 with a composition of: carbon 1.10–1.25, manganese 0.20–0.40, chromium 0.50–0.80, silicon 0.15–0.30, vanadium 0.07–0.12."

Looks like the Bokers might be the higher carbon content or European/Werkstoff type. Silver steel is just another name for high carbon steel.