Interesting this is the first one anyone has reported, as many LB7 have ben discussed here. I'm fairly clueless on the topic of stamping or heat treat processes to know how and when a modification might be made (when the steel was softer). I should study up more, because stamps and variations of stamps is one of the interesting parts of collecting to me. Codger, your observations always help with logical explanations. Salvaging the goods so they could be sold is probably right on.
In reading Harvey Platts take on collecting and stamps, he makes a relevant statement in his 1978 book:
"All goods had to be marked, but exactly which stamp was used was not considered important. If a stamp broke partway through a job, an older stamp might be used to finish the job. Many times a marking decision was made at the stamping press, according to the whim of one individual."
This statement was aimed at describing stamping practices at small American cutlery companies, but I believe we see this happened on occasion at Schrade too.
Maybe a few more of these will pop up some day, or some with a different twist.