Hi,
I looked into the suspension replacement for my cab and all the companies I called had different codes for Mk1's and Mk1 Cabs suspension, so I am sure they are different, but in what why I have no idea. To find out it's worth calling TSR or C&R and ask them - they can confirm.
C&R Enterprises - 0115 978 5740 (speak to Andrew, Roy or Steve)
TSR - 01278 453036