That is not a valid part number per Google, either. Other than this forum post, ******** and some other links come up & say it's a Bosch P/N for a starter solenoid.

If you aren't sure what the seal itself is called, what are you looking for - describe it as best as you can so we can help. Is it 6.3 (engine) specific, 109 (air suspension) specific, or is it more general & possibly on other vehicles (like the steering pump or gearbox, etc)?