Can I remove the 2 screws
> holding bulb in the temp gauge and remove the instrument panel from the
> truck, or can I heat the bulb and maybe unsolder it?
The bulb has to stay attached, if you open it then the gas that it
inside will leak out and it is ruined.
The only way to remove it is to unscrew the bulb from the engine and
take the whole assembly out.
Best thing to do is like Jim F. suggested...find one from a 56-59, they
1957 Chevrolet 3100
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959