Hi Bert - sounds indeed like your temp gauge (or the capillary tube to be more precise) is probably broken.
You can just undo the oil pressure line, so long as the engine is not running it will not leak more than a drop, if any.
I always use surgical gloves when working on the car. At first I thought it looked a little strange, but being able to just take all the grime, oil and dirt right off your hands without having to wash them makes up for that. Also it does not interfere with the work in my opinion (which is why surgeons can wear them, I guess).
I am getting ready to mail out your new member package next week, so watch for that as well ...
Cees ("Case") Klumper in Amsterdam
'69 white 280 SL automatic