Winchester 1873 44/40, model?

[jbw]

Couldn't help buying a well used Winchester 1873 in 44/40, in need for some care. In search for a carrier spring, an extractor and a new firing pin, I met the "question", first, second or third model, how do you know the difference. Number is hard to read, but might be 284215B, I am not sure of the number 4, then the number would be 28 215B.
It is a rifle with octan barrel and, what looks to me, a carbine but.
Have no pictures for now.
Second question: Where is the best place to go for parts, know Dixie Gunworks, and have looked at Homestead

[jfoxx]

Couldn't help buying a well used Winchester 1873 in 44/40, in need for some care. In search for a carrier spring, an extractor and a new firing pin, I met the "question", first, second or third model, how do you know the difference. Number is hard to read, but might be 284215B, I am not sure of the number 4, then the number would be 28 215B.
It is a rifle with octan barrel and, what looks to me, a carbine but.
Have no pictures for now.
Second question: Where is the best place to go for parts, know Dixie Gunworks, and have looked at Homestead

i might know of some parts--i think the model is determined by serial number--i live in maine, i know 2 smiths that might have some original parts--ebay sometimes has these parts listed also--need to know model tho--(1st,2nd,3rd,) regards-jfoxx

[Clyde]

Seems like the alpha suffix indicates the production changes of significance. Numrich (e-gunparts) is possible source. or Lodgewood.