Fried gauges?

Can't tell by looking at the face.
This will give you a background on how they work and some troubleshooting approaches.
Thermal-Electric Gauges (Session 227) from the Master Technician's Service Conference

For a '74 the internal resistance might be a little different than the earlier onesbut they work the same way.
Redfish has posted about that - so you can search his posts if that info is needed.

There are also some posts where people have pictures showing the heating wire and bimetal that moves the needle. Those will show you what overheating can look like.