76 is the worst year. Mine was dust. Many others years seemed just fine. I looked t a lot of years in the junk yard looking for the nonexistent 76. I bought my car with just 55,000 miles. The cluster was collapsed. The owner did not know what to do. He stopped driving it.
You will find that different years have different color cellophane printed circuits. 76 was pink. I think 72 was green. I bought the 72 thinking all were same. Each year also has different number of prongs on the plug connector. My parts yard has 20 or so pintos. Every 76 was crushed to pieces. I found that 77 had had same circuit board color, pink, and identical plug. All 77's had good solid white backplates. 78 might be same as well. I know for sure 79 and 80 have different cluster.
The former owner destroyed printed circuit on my car in a fail attempt to fix back plate.
I carefully removed pink circuit board from a junk yard 76 and attached it to the white 77 backer. All seemed well but, I lost my health. I sold the project to someone else. Did not install it.
If this information is important to you I will call him to find out if all is well.
If you can't find the 77 part, as I said the wrecking yard here has many pintos. I would be glad to get it for you if they have it, but like I said I am too sick to work. The wrecking yard is called Speedway. The number is 720-938-4055
The only worker there is Greg. It is located in Decono CO. 30 miles north of Denver. Greg once told me he shipped parts. If you have other questions send me a PM with your phone number and I will call you.
I would not even try to save 76 back plate. You will not last 5 minutes. You might also get a wiring diagram and try to convert to other years. I don't know how they differ. They all look the same to me.
If this turns out to save your project. It will do my heart good. Let me know if I helped
I have a few original light bulbs. Don't know if they are any good, but you can have them if you have need. One more thing, I believe the wagon panel differs from the sedan, but not sure. I gave the 72 panel to the new owner. It was from a wagon. He doesn't need it. If you want to try conversion, I will try to get it for you. I do not believe I have the plug. So it is not likely to help, but if you have pink circuit you may be able to alter white plastic to accept plug. Then you may not have bulb fittings for lights in correct places
Good luck
Bill