Attempting to replace brake accumulator in my 05 Prius . I need any help i can get.

I am not a mecanic but I am fairly mechanically inclined. I have read some things about the job on this forum and feel 50% confident I will fix it . I ordered a used pump and waiting on shipment . I am reading now about the numbers on them and I am concerned I may have screwed up already. The number on the car now is 44510-47050 . The part coming is numbered 44510-4-050. Does anyone know the significance of the numbers ? What they stand for and are the parts comparable ? I hope there are some of you in the know that could help me. Thanks . More questions to follow I am sure. Thanks again.