I grew up using Herter's "Model Pefect" products, including their reloading equipment that was favored by my dad, uncles and grandpa when I was a kid. They started me reloading in the 50's with it. I continued to buy some things from Herter's until they finally had to sell out in the late 70's due to some bad business decisions that George made. GCA '68 was part of it, but not the main reason they went under. Law suits, the gas shortage and some illegal imports that cost them their firearms business finished them off.
Like everything else Herter's, their products were made for them by various companies (including many in Europe). Their firearms were from firms like FN, BSA, J.P. Saur, etc; their stocks from Fajen; some of their brass was made in Sweden and some by Bell (now Mast Tech in Las Vegas), etc. I don't remember who actually made their dies, but probably CH was one of them and Saeco made their lubisizers. Herter's had several different types of dies over the years, including some that you just changed an insert in to change the cartridge it would reload. Their dies varied in quality based on the model (cost), but the top end ones were as good as any made at the time.