This is an original vintage G1 Ultra Magnus. It's the plastic wheel version in late 1986 or 1987. It's incomplete but has all necessary parts to transform and combine. No part shows noticeable plastic yellowing.

FYI: In this version, the wheels are plastic, not rubber, which is a good thing today, because plastic tires are much more durable than rubber tires. However, the truck window is omitted, the white Optimus' feet are plastic, and the fuel tanks have no chrome.

The toy is incomplete, but has all necessary parts to transform and combine. One of the two diapers (or waist, or cab connector, whatever you call it) is missing, but you actually only need one diaper. Two of the four missiles are missing, but you only need two missiles to display the figure. The original unpainted big head was missing. I was able to find a painted head as a replacement.

The trailer is in very good condition. Joints are tight, and all clips are intact. The only issue is that some screws at the bottom are rusty, but the rust can be treated with pure white vinegar. The shoulder joints are too tight. I unscrewed each shoulder and found nothing broken. It is just because the springs are too hard. Forcing the shoulders to move may break the toy, so it is up to you to choose to keep them as they are, or to find two replacement springs from a hardware store.

The truck cab lost some white paint on the die-cast chest, and lost a lot of chrome on the smokestacks and the bumper. The bottom of the cab has some minor scratches. The right shoulder and right foot are loose or semi loose. The other joints are okay.

The big head lost some silver paint on the antennas. You can touch it up with silver paint. The face is in a good condition. The forehead has a minor dent and a tiny stress mark.

Restoration suggestions:
First, I think it is okay to do nothing to this figure. It's okay for an experienced soldier like Ultra Magnus to have some battle damage.
However, if you want to do something to improve the figure, here are my suggestions as a collector myself:
1. The chrome cannot be repaired to meet the factory condition. However, you can brush paint the parts with ultra shiny liquid silver paint, and let them dry for at least 3 days (or a week if you can wait). Then carefully coat it with a thin layer of protective lacquer. Molotow liquid chrome is NOT a good choice.
2. It's not a bad choice to get two loose replacement springs for the shoulder joints, but I would still keep the original springs in case.
3. The loose joints of the white Optimus can be tightened with liquid acrylic joint fix. A lot of people did it to their action figures. However, I would only do this if the joint is too loose to hold any pose.
4. The paint of the die-cast part might be touched up spot by spot, but I doubt if the paint will stay on for very long. If you decide to completely repaint the parts, it will be the same like repainting a vintage Matchbox car. You will have to follow all steps. My recommendation is to do nothing.
5. For the rusty screws, you can carefully remove with a tiny screwdriver that matches the screw, be careful not to damage the screw. Then, soak the screws in pure distilled white vinegar until the rust is gone. Do not leave the screws in the vinegar for too long, or they will turn black. After that, wash the screws with water, sand them slightly if you like, let them dry completely, and then you can put them back.
6. The dent and stress marks on the big head cannot be repaired to restore the factory condition. However, the lost paint can be touched up. Do not use thick paint. Use thin acrylic silver paint, and you can touch it up multiple times, each time with only a very thin touch. Wait until the previous touch up gets dry or it will be a mess and you will have to start over. Based on my experience, finding a painted head is harder than an unpainted head, so the painted head is more valuable even with minor damage.
7. It's not hard to find a second diaper, and additional missiles. However, I don't think it's necessary.

Please see the picture, and send me a message if you have any question.r