Chad - I looked this up in my original Jaguar repair manual.
Firstly, I thought all inboard rear discs were solids - i.e. not the vented type. Anyway, this is the data for the solid discs:
New thickness - 0.5", min thickness 0.45"
For the fronts, new thickness - 0.95", minimum 0.90" (for the vented type discs)
Sorry - translation English to American is discs = rotors!
Can't help myself.
Other data:
max permissible thickness variation = 0.0005 (yes, 1/2 a thou)
surface flatness - within 0.0004
max run out - 0.002
If you do fit new discs, ensure the shims between the disc and the diff drive hubs are correct to centre the discs in the calipers. Plus rear end camber is adjusted by the shims between the discs and the driveshafts.
HTH
PS - same workshop manual says "Remove hub bearing grease cap and inject wheel bearing grease until no more will go in. Do not pressurise the grease, or it will be forced past the
oil seals. Refit the cap"