We had to replace a taillight (the reverse lens ran into a table leg I was putting in the trunk at a garage sale -- the table was free; replacing the taillight wasn't!). After some shopping around, we decided to go for a mail order new light assembly, since the price was close to a junkyard light with shipping and taxes.

HOWEVER. It seems that the plastic printed circuit that actually runs the lights is not automatically a part of the taillight, so what we got was a big piece of plastic. I had to gently remove the printed circuit from the old taillight to put it on the new one. The old printed circuit is worn, but workable, and the old light assembly leaked, so we're better off. But it was frustrating.

I recommend that you ask, if you're replacing your taillight assembly for any Volvo in this time period, whether the one you're getting comes with the printed circuit.