FWIW: Just a few thoughts on Model A temperature gauges:
1. Unlike brand new engines, eighty (80 +) year old engines and radiators are not much different from (80+) year old seniors with artery blockage, corrosion, high blood pressure, and leaks.
2. A temperature gauge can monitor (80+) year old harmful circulatory blockage, coolant passage pressure, and leaks to avoid harmful strokes and heart attacks requiring hospitalization and expensive organ transplants.
3. Stainless steel combined with water is best for resisting corrosion.
4. For an easy aesthetic fix which may be easy on a Model A Judge's eyes ..... is to wrap the SS tube in black wire loom sold by Model A parts suppliers ..... let the Model A Judge's guess if it is a mechanical or electrical accessory ..... and don't let them know the real answer.
Just temperature gauge thoughts.