The '91 pump assembly will work if the trans your building now has a Auxiliary Valve Body (Forward Accumulator). It will be if its a '92.
The '91 Pump Body will work on all '82-'93 700R4/4L60 Pump Covers.
You can use a '82-'84 Pump Body on '85-'93 Pump Cover, But you have to plug a hole in the Pump Cover or loss of mainline pressure WILL result. And Pump slide clearance needs to verified.
Identifying Pump Bodies.....
'82-'84, Can be used with mods, NO Partition where the arrow is pointing.
'85-'93 (And '93/'94 4L60E), Can be used, No mods, Has Partition like the pump body in the pic.
'95 & Up 4L60E, Cannot be used, Has PWM cast into the pump.