What size brakes is determined by the weight only, not motor or axle size. 4580 GVWR is the break point.
Dave
I don't know if 10" brakes would indicate a LSD but you could check the door sticker and cross reference the axle code with an online decoder. I believe there is a decoder in the tech section too.
Good luck,
Richard

You do sometimes see 10" on a 7.5 though it's pretty rare before 2000.