Brooks had three levels of quality in tailored clothing:
1. "Own Make" was made in Brooks's factory in Long Island City. It was its top of the line suit. This is the Brooks suit that the bank manager or the law partners wore. Essentially, it was a handmade suit. These were the classic, full-cut, sack suit, Brooks suits of old in heavy wools and with vests. Brooks closed the factory when it decided that it was more economical to have outside contractors make the suits rather than its own in-house factory. Under this thinking Martin Greenfield made Brooks's RTW and MTM Golden Fleece lines. However, the wheel has turned in that under its current owners Brooks decided to manufacture again. Brooks bought Southwick and and did a major revamping of the factory to make its better suits.
2. "346" was a lower level of quality-manufacture. There was less handwork, and the cloths were of a lesser quality. Hence, it carried a slightly lower price than "Own Make." However, this was not a discount or schlock line. It was a good, working executive and middle-level executive's suit. It was made by outside contractors, such as Norman Hilton.
3. "Brooksgate" was the "university shop which catered to young men in college and in their early career. This was lower priced than "346". The sizing tended to be smaller. Some older men continued to shop there especially if they were slim or short. This line was discontinued in the 1980's when the idea of a "university shop" became extinct.
On the shirts, I believe that the shirts on the main floor were all made by Brooks's factory, and they all the same level of manufacture. The Brooksgate shirts were made by an outside vendor.
It is interesting that the tie factory in Long Island City is the one factory that Brooks had kept running through the years.