I found this which shows that there are significant differences between the years:
1982 to 1984: 7.5 inch ring gear, 26 spline axle
1985 to 1989: 7.625 inch ring gear, 26 spline axle
1990 to 1992: 7.625 inch ring gear, 28 spline axle
It's a gamble, but at least you'd have parts to sell.
There might be a few options - transfer the disc's to your current axle. Transfer the axles (US term) and diff unit to the new housing?
I'd try and do a bit more research into exactly what you have(on the car and LSD), and what year this other one is.