If it were mine, I would go to the trouble to remove the gauge cluster and the sender and test them on he bench. After you are done and go to put the gauge cluster back in, do yourself a big favor and use knurled brass nuts which you can tighten without tools. I got mine from Ace hardware.

1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission