I purchased a Kodak Type 3 mercury thermometer (dual scale range to 140F/60C) in the stainless sheath from a very nice fellow APUG member. Sounds like what you are describing. Mine does show the immersion calibration mark etched into the glass.
When I got it I removed the glass, cleaned and polished until it looked new, then reset the glass. It's a beautiful instrument. It now serves as my darkroom standard. All of my other units have been calibrated to it, including a Hass Intellifaucet and the temperature compensation curve of my Zone VI Compensating Developing Timer.
If you should decide you don't want one or both of those stainless guards, or the other Fahrenheit-only thermometer, please send me a PM (Private Message) as I'd take them off your hands for a fair price.
Oh, and welcome to APUG, George...