Kitty, I don't know if you noticed up in the thread; the OP already found a used part, solving the thread's question. He posted under a different name. But your suggestion brings up another thought I had, given the high cost of the original part. It may have been a Bosch sensor originally, but I doubt it, since it was provided as part of Chrysler's ignition system.

Faced with a high price, I might be tempted to terminate that Volvo/Chrysler coaxial cable with a Bosch connector, and install a Bosch microphone in the same spot.

I'd do it myself, if I still owned a car with V/C or "computerized" ignition and needed a knock sensor for a reasonable price. Problem with doing this, and with using an unknown junkyard part, is there's no procedure to reliably know it is working correctly. The only test given by Volvo is that where you tap the block with a hammer while observing a timing light. Unless you'd done it before with a known good sensor, you'd not know how sensitive the replacement was in comparison.
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Art Benstein near Baltimore

Eat, drink, and be thoughtful.