I had the opportunity to work on a European w123 with the Sanden air conditioning compressor on it today. If anyone is ever interested it is a Sanden model number 9263. This compressor was used versus the r4 compressors that were installed on the American w123's.
It does take a different bracket than the r4 unit too. For what it is worth the s/n was 0501306780.

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Jim