Large-scale Duster electrical issue

Likely but not necessarily. Could be the wire is shorted (burned against a manifold?) so try disconnecting from the sender. But a bad IVR should affect both temp and fuel gauges if they were both working

Also you have a LOT of rust in the fuse panel, which might indicate serious leakage problems such as windshield or even (gag) rusted through cowling pan. Often, tho, the cowl fills with mud/ leaves/ etc which dams up drainage and caused water to overflow through the vent system