I've had several correspondences with Ulli Taubert, Head of Product Development at Revell Germany. Now retired.
He had been with Revell ever since the 1970s, when they developed their truck model line-up. He says the Revell Peterbilt and Kenworth kits were developed in California, when Revell was in Venice, California. Many of those kits were developed when Revell was close to moving to Morton Grove, Illinois.
He said many of the details on some of the development of those subjects were lost in the move. For instance, what prototype of trailer was the Auto Trailer based on.
He said the tooling for those kits were developed in Denmark.
He also said you can almost be assured that there will be no new to American truck subjects from Revell, and this was told to me way before Revell got bought out!
Euro model companies told me that any new tool American subjects will be coming from Moebius or some unknown future entity.