Lurtch,
based on engine number, I'm guessing you have a '69 280 SL. For a US spec car, the correct injection pump has the following longer number: PES 6 KL 70 B 120 R 20 Y.
The last 4 above (R 20 Y) are the main identifies from model to model. No idea what those other numbers are, the BBB doesn't include them.
George Davis
'69 280 SL Euro manual