Note: A “partial restoration” may only last temporarily and inflict further damage, unless you first replace all the electrolytic caps. Microphone selection will mainly depend on your voice characteristics. With most base stations during that time period, lollipop D104 mics were generally a good choice. That 3 pin mic jack is easily replaced with a 4 pin. I would swap that out and wire it internally to except the 4 pin Cobra standard. That way you can test other mics lying around to find one that will work best for your voice.