As 'Pedro' has stated the spring with the most set is generally for the driver's side and in your case the RHS, here are the part Numbers for the springs
Series 3 109 Front
RHS 265627
LHS 264563 the parts numbers are the same for both 88" & 109" the numbers can be found stamped on the underside (so it's visible to you) of the 3rd leaf (1st leaf Main, 2nd is the wrap round, 3rd leaf is the first long one)
Rear Springs
RHS 279678
LHS 279679
now there are NO guarantees that your vehicle has the original springs, a previous owner may have changed/swapped out for one or more reasons, anyway I hope the information is of some use to you, cheers Dennis
ps to check which spring has the most set, use a straight length of steel, then with a 300mm ruler from the center of the spring (opposite the center bolt) check the height between the spring and the steel bar,,.

