Um. decoding my carb...

[DRGunn]

Ok, I have a 1971 C20 with a 1978 350, with a Rochester Q-jet with the numbers on the side of - 17054927.
I know that is is a 75-79 model destination so far so good. 1705
The next thing it tells me is that it was tagged as being built in 1974. 4
The next thing is it was a special build. 9
Then it is for a chevrolet. 2
Then for a manual transmission (I have an auto). 7

Lastly, the date code is 0833, 83rd day of 1973.

Do I have all this right?

What would the special designation for the model mean?

I need to rebuild/replace this leaking carb so I can get this thing on the road.

[DRGunn]

I found it. It is a replacement carb for a 72 Vette, Camaro, or GMC.