I think the Lefever pictured above, was stamped by an unscrupulous seller at some point after Damascus was universally deemed dangerous. Lefever would never have stamped that with single letters, or in that location. The "Krupp Fluid -Essen" or "Krupp Flusstahl" markings that I have seen, have always been ahead of the flats, and sometimes nearly struck off in finishing, which tells me the gunmakers received them in the semi finished state, already marked.
The makers would sometimes use "Krupp" on top to advertise what high quality bbls. they used.
