That gearset should coincide with the different synchro setup. Yugo 4-speeds have the same ratio as well. The 128 gearset has a more even spread between gears, or so I'm told. I just donated a couple of late 'boxes to some friends for their race X effort for that reason.
Per the factory North America 128 manual (early gearbox):
first - 3.583:1
second - 2.235:1
third - 1.454:1
fourth - 1.042:1
rev - 3.714:1
final drive 4.077:1
Wagon final drive 4.416:1
* we discussed this at OR08 and it was brought up that some mid-70s sedans may have been fitted with the wagon 'box to overcome the loss of power due to the de-tuning and emissions gear to pass smog.
Per Haynes Chapter 13 Supplement:
"All models manufactured in the latter part of 1976 are fitted with a revised synchromesh and a higher final drive ratio (3.76:1)."
Per the factory North America 128 Sport L Specifications and Data manual:
final drive 4.416:1