Allen, I also had to replace this mount on one of my fridges, I couldn't locate the original part so I used a piece of rubber to replace it.
The only gray wire I see in my plans is the one that goes from the refrigerator section's light switch to the freezer fan. Does your blower still stop when you open the refrigerator's door? Is the wire that's cut still live (check with the refrigerator door closed).
As for your electrical shock, If it's not related to the gray wire that has been cut, I can tell you it's often caused by defrost heater that's shorted to the ground. It might still work but it makes the whole cabinet live.
The first thing to check (assuming the fridge has been used recently and the freezer coil is still wet) is the conductivity between each of the two blade connectors of the plug (with the plug disconnected from the outlet of course!) and the cabinet with a multimeter on the "ohms" reading. If it's still shorted, you'll see some conductivity on one of the blades of the plug and metallic parts of the cabinet (the one you touched when you got a shock should work!). If you see that there's some conductivity, you have to figure what causes that condition. If there's no conductivity, you might have temporarily "fixed" the situation by moving something or letting the freezer compartment dry from not being used for some time.
But if there's still a short, the first thing to try is to disconnect the defrost heater to see if you still have conductivity between the plug and the cabinet.
Also, I see that your defrost timer has been replaced, probably with a 4 wire model. There is probably a green wire that has been disconnected somewhere. This green wire is NOT a ground and it shouldn't touch the cabinet. Since the compressor was replaced by another Frigidaire compressor and the defrost timer also seems to be a replacement from Frigidaire, there are good chances that the person who fixed it knew what he was doing so there might not be issues with the wires. But it's still good to have a look at that.
Here are a few pics of the pages of the service manual that might help you with the wiring. I can't send you the whole manual as I don't have an internet connection at home and I'm just relying on my limited data plan on my phone.
If you find that the defrost heater is shorted, the good news is that a similar replacement part is still available. It's a bit tricky to replace but I have done it on a few similar 1964 fridges (but not on my 1963 yet!).
