1970 C10 Temp Guage - Repairable Parts Inside?

[Gromit]

My coolant temperature gauge needle is not visible at all on the gauge itself (has been that way since I bought the truck); and I've been using a hand held infrared gauge that I carry in the truck to check or keep tabs on the coolant temperature on every trip (as well as just feeling the upper hose and watching the behavior of the coolant overflow, etc. but all that manual monitoring is getting old.

I just take short (6 to 10 miles or so) trips with the truck and only once every few weeks so it has been tolerable so far. I have the bigger radiator and the biggest external trans cooler available so believe it is fairly low risk.

My fuel level, amperage, and oil pressure, speedo and lights in the gauge panel work fine and seem accurate.

The engine harness is new and the temp sensor is also new; the dash wiring and connections are clean and solid and fully inspected with no breaks.

I need help with knowing whether these 1970 temperature gauges are generally repairable or if I should just order a new one from LMC before removing and disassembling the gauge panel to see where that needle went.

I don't have a photo of the front of the gauge but here is the back panel: