Very good, Phil!!! I see that you are making much progress in developing your puny little brain! I was simply giving him information regarding the serial number. One could make the well-founded assumption that the "NI" means "nickel-plated" keys. I think Buffet no longer specifies nickel or silver in its serial numbers, but I'm not sure.
"The serial number 317870 and the model number is BC 1131,NI."
Just thinking that the serial number is pretty straight forward but we were given two model numbers to work with. I've never seen with my own eyes a model such as BC 1131, NI. Probably not very good. Tosca is the only good clarinet, right?
I'm making a lot of progress but you are trying hard to provoke me.
I just got a Buffet R13 at a 2nd hand store, it is in great shape but the bell has a hairline crack in it. This one has no model number on it either, but it has a 98xxx serial number on it. Does the crack on the bell make a difference in its value or playability? The rest of it seems in great shape. Very nice wood clarinet.
I can't say for sure. I, personally, would have checked for such things in the store before buying. Tone comes almost 90% or so out of your embochure and upper part of the clarinet (barrel and mouthpiece). I would say that if it even affects the notes, only the low f#, f, and e would be majorly affected. I don't know for sure, though, so don't trust me.
The "BC..." number is Buffet's cataloging number, also sometimes referred to as the model number, for the R13. Really, the specification R13 and "BC..." mean the same thing. The long series of just numbers is the serial number, and it can give information regarding the age of the instrument.
Chances are, the hairline crack won't affect tone too seriously. I think it really depends on the location of the crack. Down on the bell, it might not make a difference or it could make some of the lower notes out of tune. You can try sealing it with a little cork grease.