This is what I found in my research as well. And the 1351-080-031 used for 2.95 1st in the afternarket T5Z also is used in the T5’s that came in 94-95 4cyl Chevy S10. But, in that application this cog is used for 2nd gear. Same part in both applications but used with a different cluster in each.Actually 3.35 up to 2004 and then a 3.37 thru 2010.
Only the NWC 83-84 T5 came with 2.95 first however I dont think that gearset is compatible with the aftermarket 2.95 gearset.