I wouldn’t bother with a Jensen. Hit ebay for an old Pioneer or Kenwood or even go with a Custom Autosound unit that will look factory but outperform that jensen by centuries.
If your somehow determined (against logic) to use the Jensen, pretty much ANY old shaft style knobs will work (but look ridiculous if the size is way off) because the shaft size is very standard.
For the harness, try image searching and you *might* be able to make out the color code as jensen *usually* used the standard aftermarket code (but sometimes would have shared negatives on the speaker channels).