http://sheldonbrown.com/harris/derailers-rear.html
85(or 6)mm would suggest a long cage, as would the code.
as would the code.
Based on that link I'd expect "SGS" in the code if it were a long cage. It says "GS" which the page says is medium.
I'd googled the code separately and got long cage, assumed sheldon to be an out of date resource for such things, as he is with a few others now.
@Greenbank started
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http://sheldonbrown.com/harris/derailers-rear.html
85(or 6)mm would suggest a long cage, as would the code.