I believe Supplement 1 is Seismic design of steel.
So, you would be better served to go to the current version, AISC 341-05.
This is the one referenced by the new 13th addition AISC [Steel] Construction Manual, aka AISC 360-06.
The AISC 360-06 is referenced from the current building code, the IBC 2006.
However, this version funnels you into LRFD.
You could also try AISC 341-02, if that is easier to use.
This is exactly the problem, the code refers to the 1989 version, but the contractor wants to use the 13th edition for connection design. I did a comparison and most of the code is the same but compression is more conservative in the new code, and plate bending and bolts are more conservative in the old code.
I just needed this supplement to see what the new NYC code will refer to.
Yes, I agree, but in most places the results are exactly the same.
Only differences I have seen so far is that buckling is more conservative in the new code and plate bending and bolt shear are more conservative in the old code.
I only compared the clauses that were of relevance to my project though.