I can't remember how many evenings I spent with the Herter's catalog on my lap, learning all about the best, most perfect, absolute epitome of everything bearing the Herter's logo. Lots of great stuff, especially for a young policeman with two kids to feed and a mortgage to pay.
Bottom line, Herter's was a marketing company. Products were sourced all over the world, produced by the truckload or shipload, and branded as
"Herter's". I doubt they ever manufactured anything, concentrating only on what customers were buying and providing a good quality product at a very attractive price. If a manufacturer was willing to duplicate their product line under the Herter's label it probably happened; if not I expect Herter's found manufacturers ready and willing to copy just about anything to fill Herter's orders.
Not trying to be critical, just commenting on the "business model" of the company.