I have found more info:
1992 Volvo Tech & Spec dated: September 25, 1991
ABS Brakes: Anti-lock brakes will be standard equipment on all 1992 Volvos sold in the United States.
Automatic Locking Differential: The automatic locking differental is standard on all 740, 940, and 960 Volvos.
1993 Volvo Tech & Spec dated: September 11, 1992
ABS Brakes: Anti-lock braking system is again standard equipment on all new Volvo models sold in the U.S.
Automatic locking differential:
940: Both sedans and wagons are equiped with an automatic locking differential.
960: Both sedans and wagons are equiped with an automatic locking differential.
1994 Volvo Tech & Spec dated March 15, 1994
ABS Brakes: Anti-lock braking system is again standard equipment on all new Volvo models sold in the U.S.
Automatic locking differential: All new 940 series Volvos sold in the U.S. for 1994 will be equiped with an automatic locking differential as standard equipment. All 960 sedans & wagons have an automatic locking differential.
1995 940 sedans & wagons: ABS & ALD are standard as per 1995 Volvo 940 Features.
1995 960 wagons: ABS & ALD are standard as per 1995 Volvo 960 Features.
I will have the ratios and what is fitted with ABS & ALD later, I don't have it sorted yet.