I had a model 36 once in blue finish. It got some water on it from rain, and showed a couple of rust spots. I sent it back and had the factory refinish it to stainless. I lived in South Florida and the humidity was horrible. The factory sent it back and every one thought it was the model 60...but it wasnt. The factory did not stamp the frame with a refinish mark...so it was done at the factory. I wonder if maybe yours might have had the same fate.,