I'm not the person to respond to questions about original parts, LOL. That's a question for someone like Dave. Would sure be difficult to drive in northern climates, guess you could block the radiator off. Guess I can read a parts book.
The original temps are a lot lower than I thought!!!! But again, that is related to the antifreeze used. Running an engine at low temps has many negatives, increased ware, less efficient lubrication, increased slug, lower engine output efficiency, etc. Automotive engines are heat engines and efficiency (energy put into the engine vs power output) is related to operating temperature. Any heat lost out of the engine is wasted energy. This is part of why internal combustion engines are so inefficient in general, raising the operating temperature helps. A good efficiency number would be 25%, most older engines are far less.