It depends on what year, and whether they are from short or long wheel base Land Rovers.
On S2(a) LRs before 1971 (chassis suffix up to G), the wheel studs are the narrower 15/16" type, chassis suffix H has the later M16 stud with 1 1/16" (27mm). There's no real issue swapping with different studs so long as you have the nuts!
LWB rear will have 11" drums SLS (single leading shoe)
SWB rear will have 10" drums SLS
LWB front will have 11" drums TLS (twin leading shoe)
SWB front will have 10" drums SLS
Some SWB may have been upgraded to LWB front drums
Later S3s (from 79/80 onwards?) all have the same front axles that are the LWB front TLS setup.
All this is for the Rover axles, there are other axles (ENV & Salisbury) for heavy duty LWB models, these won't easily swap out for Rover axles.
I think the LWB rear axle has the springs slightly further apart than the SWB model, certainly this is the case for a Salisbury fitting to a SWB, needs the spring mounts moving.
There may also be different brake connections on the brakes between S2 and S3, whereby S3 will have metric style, but again, depends what it's off. No real problem though as the back plates can be easily taken off and swapped over on the axles.
What you seen, and what they intended for?