Well, I think it is to cause a "Schrade" search to hit the Imperials too. Some sellers will note in their text to also look for their "Schrade-Buck-Case" auctions, just so those searches will hit their auctions. To be "Pre-Schrade", an imperial would have to be pre-1946 or so. Knives of that ilk are collectable in their own right to the interested collectors. Just my own opinion.
Codger