4l0 caliper pistons 31k differences

[tout]

Ok here goes, stripped various calipers a while back
Had a peek at the left-overs and to my surprise the pistons are different lengths,and different wall thickness, one type has a concave end,the other with a raised pip ? Didnt mark any up as I assumed they were the same
Any clues as which is which, ?
T

[Norbo]

LC2 31K and LC should be the same .
F1 & N1 31K are smaller but all are the same diamator.

[Shytalk]

The ones with the raised bit in the middle are LC2 the ones ;D

[tout]

Thanks Simon

[tout]

the left one 2mm shorter LC 4L0

think i guessed wrong tho,wall thickness measures similar on both !