How to fix and restore a vintage guitar

I was at my local recycling centre yesterday to throw something away, and this older lady came out holding this guitar. I asked her if I could take it, and she gave it to me for free. I did some research on the brand, and between 1982-1990, Sunn was owned by Fender, and produced the Sunn Mustang as a Stratocaster and Precision Bass line.

The worth or rarity of these guitars massively changes depending on year. 1982-1988 is whats usually called the golden years. A lot of people liken these guitars to modern day MIM or MIA Fender Stratocasters. But usually people agree the quality of components started to drop off around 1985. They were built in India until 1988. Between 1988-1990, they were produced, many agree badly, in China.

I knew I didnt have a later 1988 model, as you can see, the headstock says FMIC, which is an indication that it was an Indian made instrument. So, I decided to strip it down, and do some further research. Here is how the guitar looked before I began:

My first step was to test the electronics. I plugged the guitar into my amp, and played a song on my phone, I held it up to each pickup on each setting, and found the neck and middle pickup were very off and on, and the tone knobs were dirty. As well as the 5 way switch.

So, I disassembled the entire guitar. I noticed on the neckplate an inspection date of 1985. What I know of Fender, this seemed odd. I removed the neck, and found a neck date on the heel of the neck. I found that this guitar was built on the 5th of March 1982. This was one of the earliest models. I then did research, and found all of the Mustang Stratocasters were HSS variations, which confirmed it. You can also date guitars of this era by pot codes, but the pots have been replaced with all 3 500k pots at some point.

Upon knowing this, I decided to fully restore it. I used a gunk cleaner all over the neck, and removed the tuners. I lifted the pickguard, and used contact cleaner on all the pots and the 5 way switch. There is an opening on the pots just above where you wire it in, spray it in there and move the knob, eventually it will feel more free.

I straightened the 5 way switch. Then I taped off the fretboard, and used a steel wool pad to polish the gunk off the frets. I removed the tape, and used a buffing action to fully restore them. I then polished and removed as much rust as possible from all the tuners, and oiled the fretboard multiple times as it was very dry. I returned the tuners to the neck, polished up the stringtree and put it to the side.

I then used my steel wool to lightly remove all the white scratches from the back and bottom of the body. I then used a polish to make the whole thing shine. I used the steel wool, along with a toothbrush, to fully restore all the chrome. I did the same, lightly, and moreso buffing on the pickup pole pieces

It was then time for reassembly. So I screwed everything down, reattached the neck, and went to restring. I noticed two adjustment screws were missing from one bridge saddle, I had spare so took them. Upon trying to string the guitar, I came to an interesting conclusion.

The nut hadnt been properly filed to take any strings at all, and the frets looked brand new. Im pretty sure this guitar had a new nut, and new frets installed before the previous owner gave it to the lady, maybe passed away and got put in storage.

So I had to file down the nut to take my strings. I unfortunately didnt have the right file size for each string, but I plan to put 10-52s on it at some point, so the larger gap isnt bad, and I didnt make it too deep either. I lastly preformed a setup, and it was done. This is how it looks now: