My opinion?
Highly unlikely to contain silver, unless there's a thin layer of silver plated on the surface (which I doubt).
My reasoning is that if they are intended to be a heater and fusible link, silver fails miserably for both functions, as it is a very good conductor, and has a relatively high melting temperature.
Are you familiar with Schwerter's solution? If you are not, you should be. Do your homework, now that I've given you the name.
Schwerter's solution is used for an instant test of silver. It displays a blood red reaction upon contact with elemental silver, and variations of the same color if the silver is alloyed. Make some and perform tests on known alloys, as well as some pure silver, so you become familiar with the reactions.
Harold