LM3 vs. VAG: Different Bosch Numbers? Why?

Dear DIY enthusiasts,

The lambda sensor for the ALH engine has part number 06A 906 461 at Volkswagen.

However, there are two Bosch part numbers associated with it: 0280 217 121 and 0280 217 122.

The last number is therefore different. Does this indicate further development, or what else could it mean?
VW sells both products under the same VAG part number.

Who knows more details?

Deleted upon request.