as far as i can remember yes it does matter, because of the shape of the absorber for the spring! Its a relativly easy job if you have the right tools!
Jack the car up, theres a bit in the middle of the car at the rear i used to jack mine up this way both wheels are off the ground.
Unscrew shock at the top (in the boot)
Unbolt shock at the bottom
clean up the spring
replace with new shock
**Do not** touch the piston with any tools what so ever, any scratches on the piston will burst the seal and wreck the shocky!
Hope that helps
:slm: