If your car has a folding mirror, then it's the later type that started in 2003. They are all the same shape after that, and many of the bits that make up the head part are the same as that on the 9-3 from 2003.
The good part is that the plastic parts are all the same, and so is the glass, for all the mirrors of that age. So you could dismantle it and refurb and paint all the bits you want to and they could be fitted quite quickly into your existing mirror metal bits. If your folding action is bad, then you do need to replace it all. I think that my current mirrors are a mishmash of bits from many mirrors!!
But, you need to look at three different wiring diagrams to sort them out. There is one for non-memory with the three wires you mention. but there is also another with three wires via the second connector that are for the folding. And then there is a third for the heated element which adds another two wires. So for the mirror you say you have, your should have eight wires.
The memory mirror would have another four.
If the mirror you buy is a memory mirror, by mistake, that function is entirely controlled in the mirror motor, so you could swap the motors and the short loom and connector. It involves a bit of excavation of mastic seal, but I've done that twice.
The hinge in the mirror does not come apart. The hinge is a tube which is crimped in place and can only be dismantled by destruction. Wires go up the tube on the folding part and cannot be withdrawn. The folding motor is hidden inside the casting and also cannot be removed. There is a small black box on the back of the frame, which is the overload protector which shuts the fold off at the end of travel or other resistance. When it fails, the mirror fold stops halfway. That also cannot be removed without cutting wires.
