That probably means that the original buyer bought the item from BLW (I also mark my jewel boxes with the vendor's name). This is an older item going back to where MTL was still part of Kadee.
Kadee Micro-Trains used to sell products manufactured by other companies. You could see that if you had some of the older issues of their monthly "News" pamphlets. The NSC Magazine has a column where they show those older issues and there many surprising things shown there.
The Kato's 50th anniversary of N-gauge models hardcover book goes into some details about the early interactions of Kato with American manufacturers/distributors. It is an interesting read.
