B4 spring help please

[zoaman]

May be a bit of a funny q but how to tell the difference between silver and gray springs on the rear of a b4.i bought it second hand some months ago and it has fitted i think 1 of each and i have a spare set which i think is also 1 of each.there is only a very slight difference in colour.1 being slightly shinier than the other.but very slight or do i have 2 sets of silver? so are there considerable diff between silver and gray?