1991 OCC with (surprise!) broken power antenna. All replacement antennas, whether power or fixed mast, do not adapt to the existing antenna lead wire. Replacing to the lead cable involves not only radio removal but disassembly of dash board.
If you need to replace your antenna but want to leave existing lead cable, Metra 40-GM18 adapter is the way to go. One end accepts a typical antenna lead wire and the other has a female spring loaded Motorola end. The part is not well known but can be found online by searching for the part number. It can be listed as Metra or Antennaworks.