puzzling fuel injector no's for 1989 300E

Purchased 6 fuel injectors for my 1989 300E. They are Bosch and all have the M-B #0-00- 078-56-23. But each has 2 other numbers below the threads one above the other that differ between injectors such as: 3 with 667 and 217, one with 565 and 204, 3 with 570 and 204, and 1 with 551 and 212.

Are these flow rates? Should I be concerned before installing?

Thanks as usual for the sage advice.