They can make multiple appliances from one set of impressions, no problem. Either the make several casts from the same mold, reuse the casts, or duplicate the casts.
Shipping between Germany and the US is a headache at the moment, though. I shipped something in October: it went by sea (!) and took six weeks to get there. Problem ist that there are considerably fewer airliners crossing the pond, thus restricting cargo capacity. Unless you're willing to pay for courier service, of course.
--SC