How do I identify which compressor is installed in my '90 745T, i.e. where is the dataplate, or what are the possibilities (DK, Sanden, York, other?), and what visible characteristics dinstinguish them?

This wagon has 271k mi and was "converted" to R134 3 or 4 years ago. I put "converted" in quotation marks because I can't verify which components were replaced. The present compressor, which has been installed since the car was new, recently started making a raucous sound, more harsh when the clutch was not engaged. Then, a burning smell, followed by no clutch engagement. At this mileage I am inclined to go through the entire system with the help of the 700 FAQ, the percentage of the work to be done by me yet to be determined. The question of whether to change compressor brands needs to be answered - any tips on identifying it before disassembling the car?